The correct answer (for me) is...it depends.
My carry gun gets cleaned at least once a month; or, at the end of any day when I've shot it. If I switch carry guns, and it's been a while since I've cleaned the stored one, I'll clean it before carrying it.
My hunting firearms get cleaned before and after each hunting season they're used for.
I also check my firearms periodically for rust, even though Arizona is fairly dry most of the time. Right now it's humid as heck here from the monsoon weather, so I check them from time to time.
I don't get completely goofy about having perfectly clean guns, but I want them to work if needed, and I enjoy cleaning and inspecting them.
Daryl
ETA-
Seems like i read some where after 20 shots the carbon from the primmers becomes a problem. Mabie it's just a rifle problem
Don't believe everything you read. While an odd thing can happen from time to time, I've never had a problem from primers, and I've shot a whole lot more than that through my firearms between cleanings. My coyote rifle usually doesn't get cleaned 'till the end of calling season. I start shooting it in mid-October, and clean it about March. By then I'll easily have a few hundred rounds through it