I think most will say that they clean it when they see accuracy fall off, which is exactly what I do. Main reason is I want to keep the barrel semi-fouled as often as possible so I dont have to worry about getting the groups tight again from a clean barrel.
My process is to obviously unload the gun, insert bore guide, grab Dewey rod and Parker Hale jag. I then run a couple of Hoppes 9 soaked patches down the bore and let it soak for 5 minutes or so, then run a couple dry patches down the barrel. I then repeat the process again, except with M-Pro Bore-Gel (no ammonia or any barrel eaters in it) and let it soak for a good 10-15 minutes, then dry patch it out. I finish up after that with a patch down the bore with some frog-lube CLP, and then run one dry patch after it, just to protect the bore.