I usually clean my rifles barrels shortly before hunting season, but will make at least one range trip to fire a few rounds through each one to verify the zero and to foul the barrel. During hunting season I don't clean the barrel even if I go to the range a few times or shoot at game.
Unless the rifle gets wet from hunting in rainy weather. Then I'll clean it, but won't use that rifle again until I confirm zero and foul the barrel again. It PROBABLY won't change and if it does it probably won't be by much, but it could, and I just feel better to verify before hunting with it. I will clean and lubricate the action to keep crud out after every shooting session as well as wiping down the exterior, but the barrels don't get cleaned unless needed
After hunting season I get to the range quite a bit in the winter, spring and early summer before weather gets too hot. If I note group sizes getting larger I will clean the barrels. Each barrel is different, some build up copper and lead faster than others. Some need to be cleaned after 100 rounds, others can go 500+.
If I get everything out to clean one, I will go ahead and clean all of my rifles at once. Most of them get the barrels cleaned at least twice a year. In addition to shortly before hunting season I'll clean them real good at some point in the spring.
If done properly it doesn't hurt anything to clean them more often. It just isn't needed, and you can damage the rifling if you get careless. Back in the days of corrosive powder and primers it was vital to keep everything perfectly clean to prevent rust.