Ah, the fitness treadmill. It's the one piece of gym equipment everyone loves to hate. Sure, you could just go running outside and get the same sort of workout in. But with a refurbished treadmill, you can easily track your time and distance, adjust your speed and incline, and even set up different types of workouts. Plus, you get to do it all within the air-conditioned comfort of a gym setting. But how do you choose the right refurbished treadmill for your gym or home workout studio? In this guide, we'll give you six tips for finding the best treadmill money can buy. Run, don't walk.