The honest limitation: we don't keep a branch in Byron, and we're not going to pretend a 19-mile drive from Holland doesn't factor into timing. On a day with several calls already routed through the east side of our territory, Byron fits easily. On a day it doesn't, you're waiting for the next run, and we'll tell you that instead of promising something we can't hit.
The other complication is parts for the handful of openers from this build era that didn't sell in volume - some mid-90s and 2000s models used logic boards that are genuinely hard to source now. If your opener falls into that category, we'll say so on site rather than quoting a same-visit fix we can't back up. Sometimes the honest answer is that replacing the opener costs less and takes less time than hunting down a board for a fifteen-year-old unit nobody stocks anymore.
We'd rather tell you that up front than take the job and string it out.