No doubt that poor humidification can cause a host of problems, including sharp fret ends, splits in the neck binding, etc. What I am questioning is whether oiling the fretboard would have any appreciable protective effect on that damage, especially if you are applying the finish "sparingly". Neal
Hey Neal,
How often you clean and treat your fretboard (if you do) probably depends on how much you play, how filthy your fretboard gets, how persnickety you are about taking care of your guitar, etc. There's not necessarily one answer that applies equally to every player.
Some people here said they do nothing, others that they clean the strings and fretboard with a cloth after each use and that's all, others that they clean and treat their fretboards once or twice a year. No one has reported having a problem following whatever method they prefer. (Though I do wonder about people who have reported having problems with sticky fingerboards. That's something I've never encountered. But it's been reported that polish that is intended for finished wood will both soften raw wood and make it sticky.)
There are oils in your fingers and if you play a lot, you are oiling your fingerboard. You may not need to do much else, but clean off the dirt occasionally that gets smooshed into the fingerboard along with the oils.
Some people perspire more than others and sweat can damage a fingerboard.
Some have a light touch, some a heavy touch. People that really grind the strings into the fingerboard are more quickly wearing away whatever may be nominally protecting it, in addition to grinding in sweat, dirt and oils. (We've all seen fingerboards that are black and oily over the heaviest played areas of the fingerboard, but where the grain of the wood is still visible in areas that don't get a lot of play.)
I'm not an expert myself. Cleaning the fretboard with 0000 steel wool and applying boiled linseed oil to the fretboard once or twice a year was recommended to me by someone who knows more about these things than I do. I've been doing that for some years, and it works for me. YMMV.
In an earlier post here I made a list of what things are NOT recommended, and WHY they aren't recommended.
Something to add: whatever you put on the fingerboard, even if applied sparingly and wiped off quickly, will still seep in and under the frets.