Shop Owners - What is your biggest headache?

Under LOI on my first shop — what's the one thing you'd fix about your daily operations?

I'm in the process of acquiring a specialty auto repair shop (niche European makes). Background is in finance, not wrenching, so I'm going in as an operator/owner, not a technician.

Before I close, I'm trying to understand what eats up the most time and money that isn't actual repair work. Things like:

- Diagnosing jobs accurately upfront vs. discovering surprises mid-repair

- Keeping institutional knowledge when a senior tech leaves

- Quoting jobs and managing customer expectations on timelines

- Sourcing parts for older/niche vehicles without tying up cash in inventory

- Getting new customers beyond word-of-mouth

If you could wave a magic wand and eliminate one operational headache from your shop tomorrow, what would it be?

Appreciate any insight. Happy to share what I learn through the acquisition process if that's useful to anyone here.