It reduces the amount of time to break in your bat. This is a COMPLETE break in of your bat, not only a certain part of the barrel, but the whole barrel and it's evenly broken in. Most composite bats get hotter as they get older. The more hits on a composite bat, the better performance you get out of it. A rolled bat is similar to having approximately 500 hits on a composite bat. Rolling will eliminate dead spots. If you don't have a rolled bat, chances are your opponent will have one and will have the advantage on your team. A rolled bat will increase the pop in your bat and that will equal more distance. I have heard but not have been able to confirm that bat rolling prolongs the life of composite bats. Your line drives will get through the infield faster which will result in more hits. I have brought bats which friends have thought were dead back to life. Bat rolling is LEGIT, it is not an alteration or modification to the bat. You will not be able to tell your bat has been rolled except by its performance. Bat rolling will NOT void the manufacturer's warranty like shaving will. There is no end cap removal.