I used to clean all my rifles to USMC armorer post-range detail specs: one clean q-tip inspection on the entire rifle. Then, I got realistic: I shoot too often to waste time like that. I found through experience that all I have to do is ensure that the bolt and carrier move smoothly and CLP the bolt carrier where it makes contact with the receiver, and the gun will keep itself clean as long as I use good quality ammo. So far, this has held true: my 20" A4 is clean as a whistle because I don't shoot it often, but my M4, which goes out with me each week, is dirty. Hell, most of you here would probably cry to see how dirty she is inside, but the beauty is that she fires true and flawlessly. I break her down shotgun style and drop some CLP on her vitals, and she continues to perform for me. I know, when I finally DO clean her properly, I'll probably cry a bit for some of the hard-baked carbon deposits, but I've found that with regular shooting, it can only get so dirty.
My AR's are super-reliable.
Now, if I were to put my M4 away for over a month or so, I'd clean her properly, but since I shoot weekly, it's just not a good use of time to clean them after each range detail.