Dry pitted steel rollers
A door built in the early-to-mid '90s usually still has its original steel rollers, and after thirty-plus years those bearings are dry, pitted, or both. What you pay depends mostly on how many rollers need swapping and whether the track has worn grooves to match the bad rollers - a door that's been riding on seized bearings for years often needs the bottom brackets checked too, not just the rollers themselves.

