It may depend upon the gun, in part. Some weapons are made to NEVER malfunction no matter HOW dirty they get or how dirty they stay, witness the AK pattern rifles.
OTOH, some very tightly-fitted competition guns may hang up if not cleaned after shooting a couple hundred rounds.
Modern guns don't require thorough cleaning with every use, however, UNLESS you're putting them away for storage of, say, a couple months or more, in which case they should be detail-stripped and cleaned and lubricated, IMNSHO. (At least, that's what I do.)
Many rifles, for instance, are more consistently accurate after a "fouling shot". The rifle is now "dirty" after the fouling shot, but still safe to be put away, as long as intended use is fairly soon.
I'm fairly fastidious about cleaning my guns, but if I were shooting several times a week instead of once a week, I'd just clean the bore, wipe off any major crud in slide rails, relubricate and reassemble. Of course, a more thorough cleaning would still be a good thing every few months, since lots of fouling and moisture-attracted lint can get in the "innards" after a while, no matter how careful you try to be, especially if the gun is used for CCW.
Modern "non-corrosive" ammunition isn't prone to etch metals, though rust can still occur in a firearm bore or elsewhere if left neglected long enough, so SOME regular cleaning is a good thing.
I do have a shooting buddy, though, who really only cleans his guns when they eventually start to malfunction at the range, and that takes a long time, probably 4-6 months, of regular weekly shooting of maybe 100-200 rounds per session, and I think it's more of a lubrication problem than a dirt problem, actually, since he doesn't clean OR lubricate them, usually! Best.
You really don't have to clean a gun after 20-30 rounds, unless you're in a severe environment. I've never had any problems with rust, even though I didn't get back to that gun for a few months to clean it.