"Improve anything you can find" is like going to your mechanic and saying "I'm going on a long road trip, can you tell me anything that needs to be fixed?"
Doing a vehicle check-up is a pretty normal thing to do, although in my case the mandatory (EU law) periodic ones are happening often enough that I generally don’t have to schedule something out of turn.
The few times I did go to a shop and ask for a check-up they didn’t find anything. Just an anecdote.
They're going to find a lot of stuff to fix.