How many people will be using the stepper? If more than one, choose a heavier stepper with a more comprehensive warranty. The ability to track the workouts of more than one user is also a nice feature.
How often will you work out? If you only plan to use the stepper a few times a week, you can choose an inexpensive model; but if you want a gym-like routine, look for a more heavy-duty machine. Experts say it's worth the investment if you use it on a regular basis.
Do you want premium features? These may include a towel or water-bottle holder, heart-rate monitor, book or magazine rack. Some even have a built-in television.
Do you prefer dependent or independent pedal movement? On dependent stair steppers, the pedals are linked, so that as one goes up, the other goes down. Independent pedal movement more closely simulates the motion of walking up stairs, because the pedals are not linked.
Do you want an upper-body workout? If so, choose a model with a twisting motion, resistance bands, or moving arms or handlebar so you can exercise your arms or upper torso as you step.
Where will you keep it? A basic stepper can have a very small footprint, and some even fold compactly to store easily in a closet or under the bed. However, some models are very large pieces of equipment that can take up quite a bit of room. In addition to floor space, take the ceiling height into consideration.