|I didn't think you ever gave that much thought. Me neither! One of the things we take for granted until it stops working. That is the latest challenge, one that, at this writing, has yet to be resolved. I took the motor out and found that the shaft was frozen. Problem is: I don't know why? I do try an fix things myself (service rates run $125+/hr), this is a case that "I know my limitations..." Stay tuned as we hope to have it fixed soon. Anyway, our new arrangement makes getting in and out of our home a bit more "athletic".