It's a little more complicated than just age. It depends on how many times a day you feed, what kind of food you feed (better food means better digestion/less waste), general body metabolism and daily exercise level.
In general, yes, they go less with age because they're no longer being fed 3 or 4 times a day.
In general, yes, they go less with age because they're no longer being fed 3 or 4 times a day.