Is this normal/okay??

[Claudia]

Hi!
Something has been going on and I don’t know if I should be worried or make any changes.
My Syrian (aka Kevin) is living in a 3,000 sq in. cage. And about 1/3 of it is a flat surface with no substrate. There are toys/hideouts/food and water in all areas of the cage. At first I thought he was living in all areas of the cage equally. But I learned that when I cleaned out his cage. All of the substrate was clean! No hoards, no poop or pee messes. No evidence of tunnels or digging, nothing! He has a sand bath and I find he is a wheel peeer. It appears that he is only living in the flat areas. The areas are all easily acessable and I’m using paper substrate which he has been on his whole life.
Please help!