I think this is the first place I ever lived in where the landlord knows that we have two dogs (and now two hens). We've had them in two places previously, and they just went for a long walk when we had an inspection. We usually left the place in better condition that it was in previously, so it was never questioned.

Cats are even easier - having had two in the past that were never 'on the books'!

I agree that the children are more of an issue. That and stupid friends who drink too much (or an angry partner who throws things at the walls - not my DP this time!).