It depends on the condition of the treadmill and its current market value. For example, routine maintenance like replacing the running belt is worthwhile on machines that are valued at $800 or more. For treadmills in the $600–$800 range, a belt replacement can still make sense depending on overall wear. With higher-end models, typically valued at $1,200 and above, repairs may include larger components such as the motor, controller, deck, or even the console or tablet. Because of their higher value, investing in these repairs is often justified.
Ultimately, the decision should always be based on the repair estimate compared to the cost of purchasing a new treadmill.