"Boys will be boys" for how long?

I am familiar with the old adage "boys will be boys" but I can't use that as an excuse for everything. With the boys being so close in age at 4, 3 and 1 they have a great time playing together, but there is a large range in size between the three of them. Their rough-housing is a part of being a boy (friends who have only girls in their lives are at a loss for words when they witness the daily interaction of mis tres hijos), I get that. I just don't know how I will survive these years of making sure they all survive, until they get to the age where they can fend for themselves!