If you want a quality indoor ride, be prepared to shell out the big bucks. "When you spend less than $500, or even $1,000, you're really just buying a disposable treadmill," says Jon Stevenson, the co-owner of Treadmill Doctor, who has spent 30 years installing and repairing 'mills for individuals, gyms, and hotels worldwide. "If you use it consistently, you'll be lucky to get a year out of it." Shop in the $1,000 to $2,000 range, he says, and you get quality or features; drop more than $2K, and you get both. Here's why the budget models aren't worth your Benjamins.

Weak motors
Underpowered motors in cheap 'mills ($500 or less) must work at max capacity, which means they end up burning off insulation on internal wiring (the resulting smell signals imminent machine death). Models in the $1000 to $2000 range use larger motors that rarely fail.

Poor wiring
Wear and tear over time forces the motor to work harder, and cheaper electrical components including the wiring can't handle the increased load. Again with the death smell.

Plastic parts
Incline motors on budget models use smaller, plastic gears, which wear out--if you enjoy simulating hills, expect a cheap buy to last a year or two. Conversely, the steel gears in spendier treadmills almost never fail, and their larger size produces faster incline adjustments.

Bad timing
Quality processors sense the resistance you put on the belt and compensate quickly for it, creating a smooth ride. Lower-end processors are sluggish--there's a lag before the belt adapts--so you feel more jerks and surges.

Stiff pieces
Higher-priced machines use rollers with steel bearing cups on the ends that resist wear. Their lesser cousins tend to use plastic cups that degrade from all the spinning, or simply seize up.

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Visit our 2014 treadmill reviews section for treadmill reviews, accessories that let you get the most out of your treadmill, and a guide to how treadmill running affects your shoes.