A straight roller replacement - all ten rollers on a standard double door, no track damage - is a single-visit job. We open the door, pull rollers one section at a time so the door stays supported, and check the track alignment as we go, since a roller that's been grinding for months can leave a groove or a slight bow that needs straightening before new rollers will run quiet.
If the track is grooved badly enough, that's a track replacement, not a roller swap, and we'll say so rather than install new rollers into damaged channel - new rollers in a worn track just wear again, faster. That's the kind of job where fixing the symptom and not the cause costs the homeowner twice.
Given the income level in Harvest and the age of the housing stock, most of what we see is a homeowner doing this once and doing it right - sealed-bearing nylon across the board - rather than patching one or two rollers and leaving the rest of the original steel in place to fail again next winter.