Depends on what you want the boat for and your price band.
I chose a boat from a good builder. It is 57ft NB suited to liveaboard as it has a solid fuel stove and a Webasto with rads. Isuzu engine, others are just as reliable.
I now have more time and more knowledge. I'd still swerve a rust bucket project type.
I was OK to paint inside and out, say £3K, allowing for time in marina to get everything sorted.
I'm happy with windows and portholes and foam insulation. Cool in summer, privacy enhanced.
Dont be afraid to look in cupboards, engjne hole, battery wiring, any wiring, plumbing,