I would check it every few days or so until you know how clean it is. Cutty has a deep one that has NEVER been dirty. The vet was suprised too when he asked if I clean it and I said not really cuz he never needs it cleaned. (I thought great, this will be the time I am wrong) Sure enough spic and span. He said it was a deep one too so he was shocked. I still do it every once in a blue moon to make sure and he likes it so why not.