You're really not saving any critical components. You'll save a very small amount on brakes and that's it. Buses already have retarders or regen. They work when you take a foot of the throttle. Very easy and simple to use.
What would really help with wear and tear is if all drivers used retarders/regen to help slow the bus down before stopping, instead of holding throttle til last second and then only using brakes to stop. If they let of the throttle a few seconds earlier, retarder/regen can slow that bus down significantly, and then use brakes to come to a full stop.