First, a couple of caveats - I shoot primarily semi-auto firearms using modern ammunition without corrosive primers. The most I have fired through a firearm in a single day is ~1,200 rounds through a Browning Hi-Power 9mm and ~850 rounds through an AR15. I have hundreds of thousands of rounds of 9mm down range on various pistols and probably close to a 100k on various ARs now.
As a general rule, I've found that guns that I use regularly rarely need to be cleaned. Where I have had a problem with cleaning, it is usually a gun that gets 50-200 rounds shot through it and then sits in storage for a year or two. So anything that is going to sit in the safe for an indeterminate amount of time, I clean and lube after cleaning.
Both the Browning and AR15 are extremely reliable and as long as you continue to add lube periodically, they will continue to run. I don't really care whether they get cleaned after 200 rounds or 5,000 rounds from a purely functional standpoint. On the ones I regularly use, the only reason they get cleaned at all is so I can remove all the carbon and gunk and examine the parts for signs of imminent failure such as cracks in stress areas, peening, etc. I don't really need to clean them for them to function; but it is difficult to do good preventive maintenance with 5,000 rounds of carbon/oil/dirt sludge in there covering everything.
I'll also add that while these rules have served me well with the firearms I own, once you add suppressors into the mix, it is a whole different story. Suppressors make everything filthier at a much higher rate. They increase backpressure and usually wear on parts. Guns that are suppressed, especially .22LR, need a much higher level of maintenance to maintain good function.