What I've found is for my EDC, I clean it regularly regardless of how many rounds I put through it. It's a carry; it'll get clogged with all sorts of dust and lint and gunky gross stuff (bleah).

As for my P365s, I've cleaned them every 500-600 rounds, just because I'm used to that interval. But I do think that they can go much farther than that if necessary...or just for the heck of it. At some point down the road I'll wind up going to the P365 as my EDC, but for now my G23 continues to serve in that role, gross stuff and all...

On occasion, just as an experiment, I've run guns until they failed in some way. Just let them get dirty and keep running, maybe lube a little, but nothing else, just to see how long they would be reliable.

I think we all might have a different idea of cleaning. I generally wipe down the major surfaces after shooting. Sometimes I don't. I detail strip about annually unless I'm finishing a shooting class or something.

Well it somewhat depends on how many rounds you shoot. It also depends on if it only a range gun or a carry gun. I like to clean after each range session, usually 200-250 rounds but that is because I will occasionally carry it. I put 300 rounds through my CZ TSO and did not rush to clean it because I had no immediate plans to carry a 3lb handgun with a 2lb trigger.

The question is how often MUST you clean it.

You can easily go 1000-2000 rounds without cleaning it, I would recommend putting lube on the places that are accessible without breaking the gun down.....barrel hood, slide rails, etc.

I generally clean my guns every 1000 rounds......I used to be a little more anal......I do put a few drops of oil on everything with a wet q-tip before going to the range.