We're booked two weeks out. I assume I need more capacity — but a third lift costs $38,000. What if I'm wrong?

The situation

Derek runs a two-bay auto repair shop with a team of three mechanics. He's turning customers away, booked solid two weeks in advance. His first instinct is to add a third lift — more bays, more throughput. But $38,000 is a serious capital outlay, and his accountant wants a better justification than 'we're busy.'

The analysis

The bays aren't the bottleneck — the single service writer juggling check-in and checkout is.

When Derek maps his workflow — check-in → vehicle inspection → repair queue → active repair → QC → checkout — the simulation tells a different story. The repair bays themselves are not the bottleneck. The single service writer who handles both check-in and checkout simultaneously is. During peak morning hours (8–10am), the service writer is occupied with new arrivals while completed vehicles pile up waiting for checkout. Mechanics finish jobs and then wait for checkout to clear before they can pull the next vehicle in.

Adding a third lift and a third mechanic would increase mechanical capacity by 50%. But if the service writer is the bottleneck, that additional capacity would sit idle much of the time — the throughput constraint doesn't move. The model shows that hiring a dedicated checkout coordinator ($32,000/year, part-time) would increase throughput by 28% and pay back in under 14 months. Adding a third lift on top of that would increase throughput by a further 18%, making the capital investment more defensible once the staffing fix is in place.

The decision

Derek hires a part-time checkout coordinator first and saves the service-writer time-per-job distribution to his library, with Monitoring watching it for 90 days before he revisits the lift purchase. Monitoring shows the fitted time holding steady — the coordinator fix is working, not just luck of a slow month — so he greenlights the third lift with actual confidence instead of a gut call.