Inclining allows you to raise the front of the treadmill to simulate walking or running uphill. This is done manually or automatically. Usually found on the least expensive machines, manual incline treadmills require you to step off the machine and adjust the positioning of the running platform by hand. While it can be a price saver, there are some drawbacks. First, these adjustments present a safety issue if you do not properly secure the deck. You could fall or crush a limb in the process of adjusting the incline. Second, frequently moving parts will cause quicker wear and tear on the machine. Third, stepping off the machine could cause you to lose motivation or momentum, and you’ll have to get your heart rate back up to get the full benefits of the cardio workout. Still, if you don’t plan on using the incline feature frequently, this won’t be an issue for you and you can get a more budget-friendly model.

Alternatively, you have the option of choosing a motorized (or automatic) incline. With this feature, users press a button on the treadmill’s dashboard to activate the incline motor to move the deck up or down. This is much more convenient as it can be done while you’re still on the machine, and it can be adjusted to the angle you want without much effort.

Whether manual or automatic, treadmills will be rated with a maximum incline and minimum decline. This is reported as a percentage grade—a number that measures the slope of the surface. The higher the percentage, the stronger the angle or slope. Most treadmills will have a maximum incline around 12%. Less common are treadmills that can simulate a decline or walking downhill, which can use muscles that usually don’t get attention in standard cardio workouts. For these machines, there will be a lowest decline number reported as a negative percentage grade.

Treadmill displays offer a wide range of features that vary greatly from one machine to another. The display can be as simple as analog LED lights that show time and distance travelled or as complex as a fully functioning TV screen with cable network connectivity. Displays vary in size and type, with higher end machines displaying more stats (time, distance, incline, speed, heart rate, workout program status, etc.) and offering more advanced features (such as a virtual tour that simulates running through real-life environments). There are positives and negatives to this level of complexity. On the plus side, sophisticated displays allow you to easily monitor and adjust your workout based on the information. They may also provide a distraction from the lull of running or walking. At the same time, this kind of distraction can be harmful to your workout because it may cause you to fall or injure yourself or be overly conscious of the clock and distance.

Advanced display screens or TV screens could have the added benefit of linking with your smartphone, so you can watch video content on the display as you run. The suite of features will be dependent on your needs, but know that you’ll pay significantly more for complex displays and TV screens - and most budget models come with a shelf for a tablet or an e-reader anyway.

The treadmill’s dashboard can have a number of useful features. A device shelf allows you to place your smartphone or tablet on the dashboard, so you can use your device—safely—while you work out. Yes, that means watching Netflix or reading an ebook! 

Similar to the device shelf is the water bottle holder. It may seem insignificant, but believe it or not, the placement of the water bottle holder can have a huge impact on your workout. You want your water bottle to be within easy reaching distance, so you don’t have to stop your entire workout to grab a drink.

Finally, some treadmills come with a built-in fan on the dashboard, which is great for some added comfort while you exercise.

Treadmills separate their warranties into three sections: Parts, Labor and Motor.

Parts warranties range from 90 days to 5 years to lifetime warranties. For light use, 90 days to 1 year might be an acceptable parts warranty, though you should not expect that machine to be very durable. You may also come across frame warranties, for which the standard is a lifetime warranty. Cheaper models might have 10- or 20-year warranties, but depending on how long you plan to use or keep the machine, that may suffice.

Labor warranties range from 90 days to 3 years. For light or moderate use, choose a treadmill with at least 1-year labor warranty. If you plan to use the machine long and often, it’d be best to find a labor warranty of 2-3 years.

Finally, motor warranties are often listed separately from parts and labor. One can easily tell the quality of the motor based on the duration of the warranty. A 90-day motor warranty would indicate the motor is likely cheaply made and not very reliable. A warranty of 10+ years would suggest a much higher quality motor.