That depends on the number of dog owners that will make use of each Dispenser. In a County or City Park setting, usage is 500-2000 bags per month per dispenser. In a Condo/Apartment or HOA setting, plan for 300-800 bags per month. Usage can vary widely however. It is best to have enough supply on hand so that you do not run out and create user inconvenience which encourages non-compliance. The Dogwaste Solutions Canada warehouse is fully stocked and we ship every order the same day, so you never have to overstock your inventory.