The visit itself is straightforward. The tech checks balance by disconnecting the opener and lifting the door by hand - a door this age should hold at half-open without sliding either way, and if it doesn't, that's a spring losing tension, not something you can fix with oil. Rollers and hinges get inspected one at a time, since on a double door built in 2001 it's common to find three good rollers and two that are cracked clean through.
After that: lubricant on the hinges, rollers, and torsion bar, a check of the cable condition at the drum, and a run-through of the opener's force settings, because a unit from that era often has the auto-reverse sensitivity set wrong from the factory and nobody's touched it since. You get a rundown of what's fine, what's wearing, and what we'd replace now versus watch for another year.