I haven't always practiced the best gun hygiene, but a fairly thorough cleaning after shooting is something I almost always do, unless I'm planning to turn around and go back to the range the very next day or something. I have three firearms that I have owned for around 30 years and have fired quite a bit, and while the bores aren't in perfect shape, none of them are in really bad shape. It's only now with this borescope that I can go back and critique what was really happening in there and what I might have done wrong along the way.
I think one of the important things I didn't do in years past, that I have been doing more recently, is to blast your bore out with some canned solvent like gun scrubber or electronics cleaner, after you use your traditional bore solvent and scrub on it with brushes or whatever you're using. The old traditional method of using your bore solvent to clean and then wiping it dry and neutralizing it with oil, I think leaves traces of solvent in there which is not good, and also doesn't clean some of the crud out of the grooves that you physically miss with your patch cloths or whatever. There were times when I was cleaning the barrel and gas block of this Mini-14 when tight-fitting patch cloths and VFG pellets were coming out looking totally clean, but then I took it outside and blasted it with electronics cleaner from breach to muzzle, tipped down over a disposable aluminum pan with a paper towel in it, and repeatedly got decent-sized batches of carbon bits that were about the size of a grain of sand.
So I have resolved to start doing that whenever I clean any of my guns, and only then come back and re-treat the barrel with some oil or dry lube. I'm sure regular old gun oil on a patch cloth re-applied periodically is a good way to prevent rust in the bore of a weapon that is stored unloaded, but in case of guns that you keep rounds chambered in, what I have always heard and read is that you should wipe the bore completely dry to avoid compromising your chambered cartridge. For my handguns that I keep loaded I am treating the bores with Eezox for that reason, since it dries completely, and the rifles at the moment have a coating of Hornady One Shot in them. One Shot seems to leave more of an oily residue but those rifles don't have a round chambered in them. In the past, a gun I kept loaded like my J-frame revolver I would have patched the vast majority of the oil out of, which is probably how I ended up with those rust spots, along with not getting all of the carbon removed when I thought it was clean, because patches were coming out clean.