Illinois's rule on modifying maintenance turns on a feature the national template does not capture: A substantial change in circumstances. For fixed-term maintenance in marriages under 10 years, a review hearing is built into the order. Retirement at full retirement age is presumed a good-faith change supporting modification. The controlling authority is 750 ILCS 5/504(f), 510(a); 750 ILCS 5/510(a-5). Parties may agree maintenance is non-modifiable; absent agreement, the court retains jurisdiction for the award’s term. Death of either party, remarriage of the recipient, or cohabitation on a resident, continuing conjugal basis (750 ILCS 5/510(c)).
Key takeaways
- Illinois calls these payments maintenance, governed for modification purposes by 750 ILCS 5/504(f), 510(a); 750 ILCS 5/510(a-5).
- The legal standard: A substantial change in circumstances.
- Only installments accruing after due notice of the motion may be modified.
- Termination events: Death of either party, remarriage of the recipient, or cohabitation on a resident, continuing conjugal basis (750 ILCS 5/510(c)).
- Parties may agree maintenance is non-modifiable; absent agreement, the court retains jurisdiction for the award’s term.
- File in petition to modify filed in the circuit court case — do not wait: Only installments accruing after due notice of the motion may be modified.
- Companion reading: Illinois maintenance guide and how to modify child support in Illinois.
Worked example under Illinois law
The illustration below uses only rules already stated for Illinois. It is a research hypothetical, not a prediction of what a court will do.
A former spouse in Illinois asks to change periodic maintenance after retirement or a drop in income.
- File a petition to modify filed in the circuit court case.
- Match the facts to the Illinois standard: A substantial change in circumstances. For fixed-term maintenance in marriages under 10 years, a review hearing is built into the order. Retirement at full retirement age is presumed a good-faith change supporting modification.
- Check whether this award can be modified at all: Parties may agree maintenance is non-modifiable; absent agreement, the court retains jurisdiction for the award’s term.
- If the request is to end support, prove a trigger: Death of either party, remarriage of the recipient, or cohabitation on a resident, continuing conjugal basis (750 ILCS 5/510(c)).
Only installments accruing after due notice of the motion may be modified. The forum is the circuit court (family division) or the Department of Healthcare and Family Services (HFS).
The legal standard in Illinois
A substantial change in circumstances. For fixed-term maintenance in marriages under 10 years, a review hearing is built into the order. Retirement at full retirement age is presumed a good-faith change supporting modification.
Courts start from the decree, not from scratch. The judge asks what the parties and the court knew when maintenance was set, what has changed since, and whether the change is significant and durable enough to make the existing terms unreasonable. The moving party carries the burden, and documentation — tax returns, pension statements, medical records, lease agreements — decides most of these cases.
Grounds that most often succeed
- Retirement. Many states now treat reaching full retirement age as a presumptive or statutory ground. Early or voluntary retirement is scrutinized: courts ask whether it was in good faith, whether it was foreseeable at divorce, and whether the recipient had a chance to save.
- Involuntary income loss. Layoffs, business failure, disability, or industry collapse — with proof of diligent job-seeking. Voluntary underemployment is commonly met with income imputation instead of relief.
- The recipient's changed need. Improved earnings, remarriage-adjacent cohabitation, an inheritance, or reduced expenses.
- Health changes. New disability or extraordinary medical costs on either side.
- Cohabitation. Death of either party, remarriage of the recipient, or cohabitation on a resident, continuing conjugal basis (750 ILCS 5/510(c)).
Grounds that rarely work: a new partner's income without statutory cohabitation, ordinary inflation, the payor's new family expenses standing alone, or a temporary dip in earnings.
Cohabitation and remarriage
Death of either party, remarriage of the recipient, or cohabitation on a resident, continuing conjugal basis (750 ILCS 5/510(c)).
Cohabitation cases are intensely fact-driven: shared finances, shared household expenses, the relationship's public character, and its duration all matter. Illinois procedure requires proof — surveillance or speculation is not enough, and the recipient gets discovery and a hearing before payments stop. Until a court order issues, keep paying.
Step-by-step: how to file
- Read the decree and any incorporated agreement. Parties may agree maintenance is non-modifiable; absent agreement, the court retains jurisdiction for the award’s term. Confirm the court retained jurisdiction to modify.
- Confirm the forum. Modification goes to a petition to modify filed in the circuit court case. If a party has moved away, UIFSA and registration rules determine where the petition belongs.
- Gather evidence dated to the change. Termination notices, disability awards, pension and Social Security statements, tax returns, medical records, or evidence of the recipient's cohabitation.
- File and serve promptly. Only installments accruing after due notice of the motion may be modified.
- Exchange financial disclosure. Many courts require updated financial affidavits; self-employment cases often add forensic accounting or a vocational expert.
- Seek temporary relief if needed. Where circumstances are dire, ask the court for interim reduction or suspension pending the full hearing — Illinois judges can grant temporary remedies in appropriate cases.
- Litigate, mediate, or stipulate. A settlement must be reduced to an order and entered before payment obligations change.
When the change takes effect
Only installments accruing after due notice of the motion may be modified.
The corollary: unilaterally reducing or stopping payments before an order issues builds arrears, interest, and contempt exposure — even if you ultimately win the modification.
Awards that cannot be modified (or are hard to change)
Parties may agree maintenance is non-modifiable; absent agreement, the court retains jurisdiction for the award’s term.
Common traps:
- Lump-sum or property-division awards styled as maintenance are usually final when entered.
- Agreement language that waives modification binds the parties even though the statute would allow a petition.
- Expired terms — once a fixed term lapses, most states will not revive it; a timely pre-expiration motion is critical.
- Jurisdiction reservations — in some states, if the decree did not expressly reserve jurisdiction to modify, no later court can.
Case law: how Illinois courts decide maintenance modification
These LawDiver opinions show how Illinois appellate courts weigh changed circumstances, retirement, and cohabitation:
In Re Support of Halas
In Re Support of Halas, 104 Ill. 2d 83 (1984)
…Therese $50,000 for the first year following the divorce as alimony and for child support and $35,000 per year alimony and child support for nine years thereafter. The parties further agreed that the alimony payments would continue in the event that George predeceased Therese. The agreement referred to the source for these payments: "It being the intention of the parties that s…
Illinois opinions such as In Re Support of Halas are cited where maintenance modification is disputed. The court stated: "Therese $50,000 for the first year following the divorce as alimony and for child support and $35,000 per year alimony and child support for nine years thereafter. The parties further agreed that the alimony payments would continue in the event that George predeceased Therese." That is the language to brief; the rest of the decision supplies the procedural posture.
In re Marriage of Petersen
In re Marriage of Petersen, 977 N.E.2d 761 (2011)
…(holding that a decree of divorce requiring the payment of alimony and child support is a decree in personam, and therefore the court did not have jurisdiction over the defendant to order him to pay support and alimony when he was served with summons outside of Illinois). In Nerini, the court had jurisdiction over the parents, but chose not to make an award that it was otherwi…
In re Marriage of Petersen is worth reading on Illinois maintenance modification because the court put the point in its own words: "(holding that a decree of divorce requiring the payment of alimony and child support is a decree in personam, and therefore the court did not have jurisdiction over the defendant to order him to pay support and alimony when he was served with summons outside of Illinois). In Neri" Use that passage as the starting point, then read the facts that precede it.
In Re SUPPORT OF MARY PAXTON BURKS Et Al.—(JAMES BURKS, Petitioner-Appellant, v. MARY PAXTON BURKS
…a lump sum property settlement in installments’ in lieu of alimony and also as and for the support of the minor children of the parties.” In the event of the death of respondent or petitioner, any installments thereafter due would abate, and respondent and her heirs would have no further claim against petitioner or his heirs. If petitioner became ill or disabled and therefore…
In Re SUPPORT OF MARY PAXTON BURKS Et Al.—(JAMES BURKS, Petitioner-Appellant, v. MARY PAXTON BURKS is worth reading on Illinois maintenance modification because the court put the point in its own words: "In the event of the death of respondent or petitioner, any installments thereafter due would abate, and respondent and her heirs would have no further claim against petitioner or his heirs." Use that passage as the starting point, then read the facts that precede it.
In Re MARRIAGE OF CAROLEE MASS, A/K/A Carolee Eichelman, Plaintiff and Respondent, Appellant and Cross-Appellee, and
…of her rights, including her inheritance rights, rights to alimony, and any claims to property held in Alfredo’s name. The agreement was submitted to the Lake County court for approval, and the court found it to be fair and reasonable and adopted the agreement as a part of the divorce decree. At the time the decree was entered, on September 23,1973, and at the time Alfredo ent…
Illinois opinions such as In Re MARRIAGE OF CAROLEE MASS, A/K/A Carolee Eichelman, Plaintiff and Respondent, Appellant and Cross-Appellee, and are cited where maintenance modification is disputed. The court stated: "Alfredo’s name. The agreement was submitted to the Lake County court for approval, and the court found it to be fair and reasonable and adopted the agreement as a part of the divorce decree." That is the language to brief; the rest of the decision supplies the procedural posture.
In Re MARRIAGE OF UTE J. CHRISTIANSON, Petitioner-Appellant, and JACK F. CHRISTIANSON, Respondent-Appellee
…order vacated the judgment of December 7, 1977, and awarded alimony in gross of $4,800 to petitioner to be paid in 24 equal installments commencing July 15,1979. The modification order also awarded $2,500 as petitioner’s attorney’s fees to be paid within one year from the date of the order, and reserved all contempt sanctions. On July 26,1979, an order nunc pro tunc was entered…
Illinois opinions such as In Re MARRIAGE OF UTE J. CHRISTIANSON, Petitioner-Appellant, and JACK F. CHRISTIANSON, Respondent-Appellee are cited where maintenance modification is disputed. The court stated: "December 7, 1977, and awarded alimony in gross of $4,800 to petitioner to be paid in 24 equal installments commencing July 15,1979." That is the language to brief; the rest of the decision supplies the procedural posture.
In Re MARRIAGE OF RICHARD H. McFARLANE, Petitioner-Appellant and Cross-Appellee, and SIRI E. McFARLANE
…ifth anniversary of a divorce decree between these parties, alimony payments will continue and will be allowed as a claim against his estate up to but not after the said fifth anniversary of any divorce decree. * 12. Wife’s Income and Form. Richard agrees that he will not urge or advance any future income or earnings of Siri from any source as a basis for Richard’s seeking…
On maintenance modification, In Re MARRIAGE OF RICHARD H. McFARLANE, Petitioner-Appellant and Cross-Appellee, and SIRI E. McFARLANE speaks to the Illinois dispute in this passage: "ifth anniversary of a divorce decree between these parties, alimony payments will continue and will be allowed as a claim against his estate up to but not after the said fifth anniversary of any divorce decree. * 12. Wife’s Income and Form. Richard agrees that he will not urg" The surrounding opinion shows how the court applied that language to the record.
In Re MARRIAGE OF ROSEMARIE LEHR, Petitioner-Appellant and Cross-Appellee, and LOUIS A. LEHR, JR
…trial court which reduced the amount of monthly unallocated alimony and child support (the monthly obligation) that respondent, Louis Lehr, an attorney, was obligated to pay pursuant to a marital settlement agreement entered into by the parties at the time of their divorce in 1977. Rosemarie also appeals from an order which required Louis to pay only $3,800 of her attorney fees…
Illinois opinions such as In Re MARRIAGE OF ROSEMARIE LEHR, Petitioner-Appellant and Cross-Appellee, and LOUIS A. LEHR, JR are cited where maintenance modification is disputed. The court stated: "Louis Lehr, an attorney, was obligated to pay pursuant to a marital settlement agreement entered into by the parties at the time of their divorce in 1977." That is the language to brief; the rest of the decision supplies the procedural posture.
Practical checklist before you file
- Identify which type of maintenance your decree awards — the modification rules differ by type.
- Confirm the decree or agreement does not bar modification.
- Document the change with third-party records, not just testimony.
- For retirement motions: assemble pension statements, Social Security estimates, the divorce-era financial disclosures, and evidence of good faith.
- For cohabitation petitions: gather admissible evidence and expect a discovery fight and an evidentiary hearing.
- Keep paying until the new order is signed; calendar the effective-date rules under 750 ILCS 5/504(f), 510(a); 750 ILCS 5/510(a-5).
- Search LawDiver for recent Illinois appellate decisions before filing.
Frequently asked questions
Can maintenance be modified in Illinois?
Yes, in most cases. A substantial change in circumstances. For fixed-term maintenance in marriages under 10 years, a review hearing is built into the order. Retirement at full retirement age is presumed a good-faith change supporting modification.
Does retirement end maintenance in Illinois?
Retirement is a recognized ground in Illinois — 750 ILCS 5/504(f), 510(a); 750 ILCS 5/510(a-5) governs how courts weigh it. Reaching normal retirement age carries more weight than early or voluntary retirement, and the recipient's own retirement readiness is considered.
Does my ex's cohabitation stop maintenance?
Death of either party, remarriage of the recipient, or cohabitation on a resident, continuing conjugal basis (750 ILCS 5/510(c)). You must petition the court and prove the statutory elements — the obligation does not end by operation of the new relationship alone until a judge so orders (unless Illinois's statute makes termination automatic on remarriage).
Can maintenance be increased?
Yes, where the statute permits. Recipients who prove a material increase in need — often medical — can seek upward modification, subject to the payor's ability to pay.
Can Illinois courts modify maintenance retroactively?
Only installments accruing after due notice of the motion may be modified.
What if my maintenance was set by agreement?
Parties may agree maintenance is non-modifiable; absent agreement, the court retains jurisdiction for the award’s term. Agreements matter: read the incorporated terms before assuming a petition will be heard on ordinary changed-circumstances grounds.
Related guides
- How Illinois calculates child support
- Illinois maintenance / alimony guide
- How to modify maintenance in Illinois
- How to modify child support in Illinois
Disclaimer
This guide is general legal information about modifying maintenance in Illinois, not legal advice. Statutes and case law change. Confirm the current text of 750 ILCS 5/504(f), 510(a); 750 ILCS 5/510(a-5) and consult a licensed Illinois family-law attorney about your decree before filing or changing payments.