There is much debate over this topic, and many factors go into the answer. Here is my method, and why I use it. First, I shoot often. Usually weekly or bi-weekly which makes cleaning guns a lot of work. Many people will tell you that guns need to be cleaned each and every time you shoot them. Can you over-clean your guns? No. As long as you are using safe cleaning chemicals and practices it will not hurt your gun.

I for one, do not have an extra 30 minutes to an hour every time I shoot to clean them afterwards. I usually clean my pistols about every 5th time I shoot them with time permitting. If I shoot suppressed, I usually try to do it every 3rd or 4th time due to the extra carbon. Rifles are a different story. The .22 rifles will get dirty rather quickly because I usually send a few hundred rounds down range each time I shoot them. With the amount of rim fire ammo and type the internals can get caked up enough to cause feed problems.

Center fire rifles like AR-15s will get pretty dirty. The design and mechanics of the gun put carbon in every nook and cranny possible. So, if you want it spotless be prepared to spend some time cleaning it. I have gone months, with over 1000 rounds fired and not cleaned or oiled the weapon. It still fired and I never had any problems until I decided to clean it. What a mistake, it was 10 times harder to clean once the large amount of carbon was able to sit on the internals and cake onto all the metal parts. I try to clean ARs and shotguns every 3 or 4 times I shoot them to avoid this problem.

You may also wish to read another article covering the tools and chemicals for cleaning guns.