I know a few mail carriers. 1. Decent pay plus good overtime 2. Great benefits 3. Insane pensions 4. They can do their routes in about 3 hours if they hurry. But they don't work for Fedex so why push it.
I used to be a carrier and still have friends that work there. It used to be you could get done in 3 hours and hide out but those days are over.
You now swipe your badge at various check points so they can track you.