Incline Percentage - While most people workout at a 2 to 4 percent incline, most high-end treadmills go to about 15 percent. If you're prone to shin or calve injuries, you shouldn't use a high incline and this feature should not be the first priority on your treadmill shopping list. Incline Adjustment - While lower costing treadmills will come with a manual incline that moves as the runner presses a button, more expensive models will change automatically to match the runner's heart rate. Many treadmills will also feature workout plans that adjust consistently throughout a specialized workout that you choose.

Running Surface - Depending on your size, running style and stride, you may need a wider or longer track. It is suggested that you take a practice jog on a treadmill to make sure that it fits your surface needs before purchasing it.

Motor - The commercial treadmills that you use at the gym are most likely powered by AC motors that make a lot more noise. Many home treadmills use a DC powered motor, which can be quieter. There are no real advantages or disadvantages to either.

Running Belt - If money isn't necessarily an object, it is suggested that you buy a treadmill with the best running belt on the market. Because they are constantly being used during a workout, running belts tend to be the first thing to be damaged. Starting out with a strong belt could save a lot of time and money in the future.

Speed - You should shop for a treadmill that is built specifically for your speed and style. If you tend to walk more, speed should not be an issue as most models have slower paced settings. However, if you are more of a runner, you may need a heavy-duty version. Dashboard - Most treadmills have simple dashboards that give runners a basic reading of distance, time and speed. More expensive models will have dashboard with more features, including heart rate and calories burnt.