Plenty of what keeps a door running is homeowner-level work: wipe down and lubricate the rollers and hinges with a garage door lubricant (not WD-40, which washes grease out rather than adding it), check that the track is clear of debris, and tighten the mounting bolts on the opener rail if they've worked loose. On a 1972-era door, also look at the bottom panel seal - the moderate cold winters this region gets will crack an old seal faster than it looks, and a cracked seal lets more cold air and moisture into the garage than most people expect. What you shouldn't touch yourself: the torsion spring, the cable, or anything under tension. That's true everywhere, but it matters more on an older door where the spring may not be sized to current standards, which changes how much force is stored and how it behaves when it lets go.