A quick clean-up after a range trip keeps mine working just fine. After every third or so outing, I do a complete cleaning. This is how I treat almost all my guns, not just the AR, so it is no more of a pain than cleaning the 10/22 or the bolt-actions. If you have the right cleaning tools, ie: chamber brush and gas tube brush, life will be much easier when it comes to cleaning. This has kept my AR's running fine after several thousands of rounds.
Silencers have NEVER been illegal !