If you're in Chicago, it's even longer than 21 days. It's just short of forever.

The Chicago Public Library recently abolished all late fees, forgave existing fines, and now if you check out a book, it automatically renews something like 99 times.

"a system that for years has locked out library users when they accrue $10 worth of fines — a penalty that disproportionately affects poor families who need free access to books and high-speed internet the most."

"one in five cards that are blocked in Chicago belong to kids under the age of 14"

https://chicago.suntimes.com/2019/9/30/20890138/chicago-publ...