I know there is debate about hydrating the fretboard.

How often ?

Lemon oil or a different oil.

lots of bare wood inside the body of an acoustic instrument whether guitar or ukulele.

Good old YouTube, I have just watched a tuber pouring oil inside the body, letting it swill around and pouring excess out of the sound hole.Supposedly to improve the tone of the instrument. [br]I could understand why someone may want to treat or protect bare wood but if it truly improved tone I'm sure it would be advised much more readily.

This was the first time I have seen it proposed and it seems quite weird.

Dave