I bought my '87 O'Day 40 five years ago and have been working on it since, preparing for my retirement this summer and becoming a live aboard.
When I bought it I knew I had much to do. Since the purchase I have replace just about every mechanical and electrical item on the boat, except for the engine ( which only had 1000 hours on it), plus some hull fiberglass work, all of which I knew I was going to have to do, and why I only paid $25,000 for the boat.
Last fall I pulled the mast and have been working on it replacing the lights and new wiring.
This summer the new solar panels (400 watts) and wind generator (650 watts) will go, on along with the AIS I just got.
I have a 5 battery house bank and think I am gong to add two more - can never have too much - I have a lot of electronics ;-) plus a backup starter battery.