Coaches can set whatever playing rules they want, and it's up to parents to decide what they're looking for.
As for me, and 10U, I don't believe in any players sitting out 1 whole game, much less 2-3, unless it's a discipline/commitment issue. I'd be happier w/ 11 players and not adding a 12th, unless you have a lot of absences. At 10U, everybody showed up every weekend, so I never needed 12. In fact, I had no more than 10.
As for me, and 10U, I don't believe in any players sitting out 1 whole game, much less 2-3, unless it's a discipline/commitment issue. I'd be happier w/ 11 players and not adding a 12th, unless you have a lot of absences. At 10U, everybody showed up every weekend, so I never needed 12. In fact, I had no more than 10.