As usual, mine has simple wording:

Late/Early Fees: For every 30 minutes early/late you will be charged $5 at the time of pick up or on the following day. Minutes will be rounded up to the nearest half hour interval. An early/late fee of $5 will apply for each incidence where drop off or pick up occurs before or after stated hours of business (7:30am – 5pm) or when a 9 hour day is exceeded. Advance notification is required whenever an early/late time is required.

A late fee of $5 will be charged for every day that payment is not made at the end of the week.