Lubricating hinges and rollers, tightening loose bolts on the track brackets, checking that the auto-reverse still works - those are fine to do yourself, and doing them twice a year on a door this age is worth the ten minutes. Torsion springs are not on that list. A spring sized for a mid-90s door is under real tension, and the tools to wind it safely aren't something most garages have lying around, regardless of how many videos make it look simple.
If the door is dragging or the opener is straining, that's also not a DIY call - a motor working against a bad spring burns out faster, and a replaced motor on top of an unreplaced spring just means paying for the spring job twice.