A torsion spring under tension can break a hand or worse, and that risk doesn't change based on how new the door is. If a spring's gone, that's not a YouTube-Saturday job - the winding bars and clamps matter, and getting it wrong on a double door means a lot of force let go in a small space.
What you can reasonably do yourself: check the track for a bent section, listen for a grinding roller, test whether the safety sensors at the bottom of the track are aligned (a blinking opener light usually means they're not), and lubricate hinges and rollers a couple times a year. None of that requires a call.
Honest limitation: not every opener model or specialty part rides on the truck. If your unit needs a specific circuit board or a belt kit we don't carry that day, the visit turns into a diagnosis first and a second trip to finish the job. We'd rather tell you that up front than pretend every job wraps in one stop.