Don't touch the torsion spring yourself. On a commercial door this wide, the spring is wound to a tension that can break bones or worse if it releases while you're adjusting it, and that's true whether the door is ten years old or thirty.
What you can reasonably check yourself: whether the track bolts are visibly loose, whether the sensor eyes are aimed at each other and not knocked sideways, and whether the opener's limit settings have simply drifted (most units have a reset procedure in the manual). If tightening a bolt or re-aiming a sensor fixes it, good - that's a fix that costs you nothing.
If the door is dragging unevenly, stalling under load, or the spring has already let go, that's a call, not a project. The tension involved on a 12-foot commercial bay isn't comparable to a single-car residential door, and the failure mode when it goes wrong is a lot worse.