9. Changing Clothes at the Gym. Dressing at the gym can be a big time-waster. Change before leaving work or the house and you're less likely to change your mind about working out once you hop into the car, Trese suggests.
You're also less likely to get into a conversation in the locker room that could shave 10 minutes off your workout.
"Some people even go to the extreme where they wear their workout clothes to bed so they can just get up and go," says Trese.
If you don't like the idea of sleeping in shorts and T-shirt, try laying out your workout clothes the night before to save time in the morning.