Over 5.5k on my 8fun cst original clutch /planet gears but have replaced bearings.Mid-drives tend to require a chain replacement around every 500-1500 miles, depending on the amount of power and the type of riding (muddy off-road riding covers the drive chain in what amounts to a grinding paste). Direct drive hub motors fall at the other end of the maintenance scale and might require a bearing swap after 10,000 miles. Geared hub motors fall into the middle and tend to require a clutch & planetary gear replacement after 2,000-4,000 miles or so.