The call-out fee is the fixed charge for a mobile mechanic to bring the shop to you — it covers drive time both ways, the service truck itself, and usually the initial diagnostics. It exists because a two-hour round trip is two hours the mechanic can’t bill anywhere else. In every RIG bid the call-out fee is stated upfront, so it’s part of your comparison, not a surprise line item.
Think of it as the price of "you don’t have to get the truck to the shop." A mobile heavy-duty service truck is a rolling six-figure investment — air compressor, generator, welder, crane on some, plus parts inventory — and the tech driving it is billable talent spending an hour each way on the road for your job. The call-out fee is how that math works for jobs of any size; without it, no one would roll for a 20-minute belt swap fifty miles out.
What varies: distance (many mechanics price bands by mileage), hour of day, and whether initial diagnostic time is bundled — commonly the first half hour of looking is inside the fee, with the hourly rate starting when wrenches turn. It is fair to ask any mechanic exactly what their fee includes; through RIG, that is visible per bid, and comparing two bids often comes down to one having a longer roll than the other.