The 15-day rent payment grace period in Maine

[Eric Pierpont]

I told my tenants they would not be charged a 4% late fee until 15 days from the time payment is due. The 15-day grace period is state law which I will abide by. So now tenants do not pay me until the 13th or 14th of the month which is annoying. What would be a good way next time around to present a stricter payment policy while still abiding by the law?