Re: What you wish you did when you got your boat?
I'll answer the inverse of the question - what did I do that I'm glad I did? The boat had a few years on her, so we went through EVERYTHING to make her ready for cruising. Bought a sewing machine and made cushions and sail covers, replaced hoses and pump rubbers, checked all wiring, puzzled over the watermaker procedures, and so on. It wasn't that she needed so much work (cushions aside), but it gave us intimate knowledge of all systems, and the confidence that if something was amiss we would notice it and know how to fix it.
My only regret was fitting a brand-new impeller to the engine, using one from the spares that were aboard. A month and 10 engine hours later, 2 miles into a 300-mile trip, the engine got warm. All three of the spare impellers that the previous owner had accumulated were deteriorated with age. So lesson learned - rotate anything rubber every two years at least.