The median home in Hacienda Heights went up around 1968, and a lot of garages here still have whatever opener got bolted to the ceiling joist back then. That's not a guess about age - it's the math. A chain-drive unit from that era has no photo-eye safety sensors, because those weren't required until the early 1990s. The gear is plastic by now regardless of brand, and plastic gears from the Johnson administration don't hold up. What usually fails first isn't the motor. It's the trolley carriage, the drive gear, or the capacitor that was never swapped because nobody thought to.
The mild temperate climate out this way is actually a point in the hardware's favor - you're not fighting rust from humidity or cracked housings from freeze-thaw. So when an opener from 1968 finally dies here, it's almost always wear, not weather. That changes what we check first: gear condition and sensor compliance before anything else, since the rest of the unit was built to outlast its own electronics anyway.