I have 3 dog runs, that the dogs stay in (if the weather is good) all day. The runs are 6 x 18 (2 of them) another run is 18 x 12. I clean them everyday and add fresh shavings once a week (most of the runs are grass but the shavings helps for the dirt areas). I use to have a decent sized dog yard at the back of the house, until a recent storm knocked down a bunch of trees and my fence lol) so now its small 20 x 20, it only gets cleaned once a week usually but it is only used to potty them quickly from the house.
All students have to pick up after their dogs AND take it home with them. I have to check the parking area and outside of the training rings because of my neighbors dogs which always leave deposites.
Students are told that IF they don't pick up after their dog, they get 1 warning, after that they are asked to leave and DON'T get a refund. Has not been a problem yet. I hate when folks don't pick up after their dogs.