We started off life with some sort of long service varnish/stain type muck, that the previous owner had, I believe) put on with a spade! From memory, I believe that cost us about £750 to have removed (in Greece). From that time on, we kept it bare, washing it only in salt water and lightly sanding and putting on a thin coating of Teak oil from time to time.
This gave rise to a fully sailable and serviceable finish and endless desires from my wife to have her varnished, which i (as Captain) vetoed and without hesitation.
I think it worked, as we now have another boat (331) and I have so far not heard any suggestion about coating it. Mind you, I do now have hearing aids and a strong conviction that I would still veto it. Time has moved on and although my wife is now Captain, I am now Admiral – so she would not stand a chance!