Commercial ellipticals usually are built with more bearings than bushing. Preventative maintenance is still as necessary as doing repairs when they become noisey. They are best to be checked and serviced every six months under moderate use. Constant use should be checked every three months. They should be checked for play in joints and greased where needed. Drive belts are usually needed in the five year time frame. At that point, cleaning and replacing drive belts and any worn parts is a good idea. To insure less rebuilding from this point, keep them on the general maintenance calls to keep down repair cost. Self-generating units should be check for new belts every 3 years. Keeping them clean and free of sweat will prolong their life to.