Placentia's housing stock centers on 1976, noticeably later than the 1960s-and-70s mix that covers most of the broader service area. That matters for maintenance because by the mid-70s, tract builders had mostly standardized on steel sectional doors with extension springs mounted above the horizontal track, not the older torsion-only setups you find in earlier neighborhoods. If your door is original, you're looking at extension spring hardware that's now approaching 50 years old.
What you can safely do yourself: wipe down and lightly lubricate the rollers and hinges twice a year, check that the photo-eye sensors near the floor are clean and aligned, and look over the cables for fraying. Tighten loose bolts on the track brackets - vibration works them loose over decades.
What you should not touch: the extension springs themselves. They store a lot of energy, and on a door this age the stretched steel is more likely to have developed fatigue you can't see from the outside. Same goes for the safety cables that should be threaded through them - if yours doesn't have one, that's a repair call, not a DIY fix.