Best Interests of the Child Illinois: The 17 Factors Judges Actually Use

Where the Factors Come From

When Illinois parents can't agree on a parenting-time schedule, the court decides for them using the "best interests of the child" standard. That phrase sounds subjective, but it's actually driven by a specific list of factors codified at 750 ILCS 5/602.7(b). Judges are required to consider all of them — and barred from relying on any factor that's not connected to the child's welfare.

Understanding these factors isn't just useful for trial preparation. Even if you settle through mediation or negotiation, the best-interests standard is the backdrop against which every proposal is evaluated. Knowing what the court cares about helps you build a proposal that a judge would approve.

The 17 Factors

Here's the full list from the statute, with the practical significance of each:

1. The wishes of each parent. The court considers what each parent wants, but no parent's preference alone determines the outcome.

2. The wishes of the child. Considered in light of the child's maturity. Illinois doesn't set a specific age at which a child's preference controls — a mature 10-year-old's input may carry weight, while a 14-year-old's preference might be discounted if it's driven by which parent has fewer rules.

3. The amount of time each parent spent performing caretaking functions with respect to the child in the preceding 24 months, or, if the child is under 2 years old, since the child's birth. Historical caretaking data — who did the school runs, doctor visits, and bedtime routines — carries real weight.

4. Any prior agreement or course of conduct between the parents relating to caretaking functions. The way parents have handled caregiving in practice can help show what arrangements have worked.

5. The interaction and interrelationship of the child with their parents, siblings, and any other person who may significantly affect the child's best interests. Courts look at the quality of existing bonds, not just the quantity of time spent.

6. The child's adjustment to home, school, and community. A child who's thriving in their current school district and neighborhood has stability the court is reluctant to disrupt.

7. The mental and physical health of all individuals. This applies to parents and child alike. A parent's untreated mental health condition or substance issue is relevant only if it affects their ability to care for the child.

8. The child's needs. The schedule should account for the child's day-to-day needs, including medical, educational, and developmental needs.

9. The distance between the parents' residences, the cost and difficulty of transporting the child, each parent's and the child's daily schedules, and the ability of the parents to cooperate in the arrangement. Practical logistics matter. A 2-2-3 schedule doesn't work if the parents live 45 minutes apart and the child has school at 7:30 AM.

10. Whether a restriction on parenting time is appropriate. Restrictions are considered when the evidence shows they are needed to protect the child.

11. The physical violence or threat of physical violence by the child's parent directed against the child or another member of the child's household. Any such history is relevant to the child's safety and the parenting-time analysis.

12. The willingness and ability of each parent to place the needs of the child ahead of their own needs. The court looks at whether each parent can put the child's needs first.

13. The willingness and ability of each parent to facilitate and encourage a close and continuing relationship between the other parent and the child. This is the "friendly parent" factor, and judges take it seriously. A parent who badmouths the other parent, blocks phone calls, or makes exchanges difficult is hurting their own case.

14. The occurrence of abuse against the child or another member of the child's household. Abuse is considered separately from the physical-violence factor.

15. Whether one of the parents is a convicted sex offender or lives with a convicted sex offender, and, if so, the exact nature of the offense and any treatment successfully completed. The parties are entitled to a hearing on the issues raised by this factor.

16. The terms of a parent's military family-care plan. This applies when a parent is in the military and subject to deployment.

17. Any other factor the court expressly finds relevant. This catch-all allows judges to consider circumstances unique to the family — special-needs children, a child's competitive sports commitments, or other facts tied to the child's best interests.

The 24-Month Caretaking Lookback

One of the most powerful tools in Illinois custody cases is the caretaking-functions analysis under 750 ILCS 5/602.7(b)(3). The court examines who has been performing daily care tasks over the preceding 24 months, or since the child's birth if the child is under 2 — school pickup, homework supervision, meal preparation, bedtime routines, medical appointments.

This isn't about who earns more or who has a more flexible work schedule. It's about documented involvement. A parent who has consistently been present for these daily functions has a strong foundation for requesting substantial parenting time.

That caretaking window also means that decisions you make right now — during separation, during temporary orders — are building the record the court will use to decide your final parenting plan.

How to Organize Your Evidence

Don't wait until trial to start thinking about these factors. Document your involvement systematically: keep a log of school events attended, doctor appointments managed, homework help provided, meals cooked, and bedtime routines handled. Save communication records that show cooperation (or the other parent's refusal to cooperate). Note the child's adjustment to their current home, school, and social environment.

The Illinois Child Custody & Parenting Plan Guide includes a caretaking documentation log organized around the 17 best-interest factors and a decision-making worksheet that maps your evidence to the factors the court will evaluate.

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