You are buying a very sweet boat, but be sure to include an engine survey. I assume the boat has the original A4, so the cost of a replacement would be only half that of a diesel, but given that its gas, all the more reason to start off knowing it is shipshape.
Minimal things typically done annually include;
1. engine oil change, new impeller and tuneup
2. clean and wax topsides
3. service
winches ( you have a lot of these...)
4.
paint bottom as needed
5. replace zincs as needed
6. clean/coat/recoat exterior teak
7. service/check seacocks
8. check all
lights
I'm sure I've missed some. You might also ask the PO what was on his to-do list, as this becomes your to-d0 list, but don't expect that the PO will be too forthcoming, whatever he/she may be hiding will remain hidden, that's the way it works.