Actually, IL has very broad probate rules. The Illinois Probate Act allows a decedent's estate
to be re-opened at any time after the estate has been closed "to permit the administration of a newly discovered asset or of an unsettled portion of the estate on the petition of any interested person."
So you can reopen at any time if there is a newly discovered asset, or if a portion of the estate was not settled. Probate for this never closes.
Now...what if the estate was settled and there are no new assets? Are they any other ways to reopen?
1. It may be sued by persons who failed to receive proper notice of its opening or closing. So if this happened...if someone was a heir
and never received notice, they can sue to reopen the proceeding. There is not a direct "statute of limitations" though laches will apply, so the person should apply as soon as they discover the error.
2. It may be sued for fraud or concealment of assets by the Personal Representative for up to 2 years after discovery of the fraud.
Let me know if you have more questions...happy to assist if I can