If I still had one of my copies of The Accurate Rifle By Warren Page (the down side of lending books to new shooters without writing it down) I could give you the page on which I believe he said that just for kicks, he once went a whole season without cleaning a case neck or primer pocket...and did very well.
On the inside of neck thing, I brought this up in conversation with a shooter that has been in the sport for years, make that decades, and is near the top of the hall of fame, and he told me that he never cleans them, because he has proven to himself that he gets a more consistent bullet seating force leaving them as fired. I am guessing that this would absolutely be impossible for the stainless pins and tumbler crowd, but at 1-300 yards, I am sure that none of them shoot as well as he does. So, there you have it. As a tactic to disadvantage your competition, do a lot of talking about the importance of spotless brass ;-)
Getting back to the primer pocket thing, has anyone actually proven to himself that uniform pockets and cleaning them does anything for accuracy? I clean them, and in the past used a carbide tool that Russ Haydon sells that is specifically designed to remove an overly large radius in the bottom corner of the pocket, that would keep a primer from seating properly. I have not run into a box that needed that for some time, but it has been a while since I bought a new box. It may be that Lapua simply made the problem go away.