If your plane is excessively worn or damaged making it no longer airworthy, chances are you’ll need to hire an A&P mechanic to do the required work. If you have mechanical skills, an A&P mechanic may allow you to do the work under his or her supervision.
You probably aren’t going to try to do an engine overhaul yourself — at least not the first one — but many aircraft owners can do repairs on the craft’s metal or fabric skin under supervision. Engines in most modern aircraft have a time between overhauls (TBO) of 1,800 to 2,400 hours. It is important that your aircraft’s engine log includes all maintenance records including when they were done as reported by the engine tachometer or Hobbs meter.