A torsion spring job on any door built in this era is not a homeowner repair - the spring is wound under enough tension to break a wrist or worse, and that's true whether the door is 5 years old or 35. What you can reasonably handle yourself: tightening loose hinge bolts, lubricating rollers and hinges, and swapping a worn bottom seal, which matters more here than in a milder climate given the severe cold winters this region gets.
What you shouldn't touch: the spring itself, the cable drums, or anything involving the opener's force settings on a unit old enough to predate current safety standards. If your door is fighting you - reversing halfway, slamming the last foot of travel - that's a symptom worth a call rather than a YouTube fix, because on a 1990s-era door that behavior usually means the spring has already lost tension and the opener is straining to compensate.