815 ILCS 375/11: Delinquency charges.

A retail installment contract may provide for a delinquency and collection charge, on each installment in default for a period of not less than 10 days, in an amount not exceeding 5% of the installment on installments in excess of $200 or $10 on installments of $200 or less. Only one delinquency and collection charge may be collected on any installment regardless of the period during which it remains in default. In addition, a retail installment contract may provide for the payment by the buyer of reasonable attorney's fees incurred in the collection or enforcement of the contract. Any clause or provision of any retail installment contract entered into after December 31, 1973, to the contrary notwithstanding with respect to attorney's fees incurred in the collection or enforcement of such contract, the court in its discretion may award attorney's fees to either party as the interests of justice may require.