A commercial overhead door is not a bigger version of a house door. It runs more cycles a day, it's usually on a higher-cycle spring or a jackshaft opener, and when it jams half-open in front of a loading bay, you've got a crew standing around instead of working. Some things a maintenance person can handle: tightening a loose bracket, clearing a track of debris, swapping a worn weatherstrip. Once you're talking about a broken torsion spring, a bent track rail, or an opener that's tripping its overload every third cycle, you're past the point where a screwdriver and an afternoon fix it. Commercial springs are wound under far more tension than residential ones, and they're the single most common cause of an ER visit tied to garage doors. If the door is heavy enough to need a crew to lift it, it's heavy enough to hurt whoever's guessing at the repair. Know the line: cosmetic and routine, you can probably do yourself. Anything involving spring tension, cable, or the opener's drive system, call it in.