Out of necessity, lately it's been Grayfurnaceman (https://www.youtube.com/user/grayfurnaceman) for home HVAC/appliance repair and Scotty Kilmer (https://www.youtube.com/user/scottykilmer) for auto repair.

For fun: Amarguitar for Phish guitar solo analysis and lessons: https://www.youtube.com/channel/UCP31spBZuvhmXf2gz9ugO8w