Well, Okay....
First; TL;DR. I'd bet my next Social Security check that you have 8 pages of comments and advice, ranging from "you're crazy; don't ever put anything on that Rosewood fretboard" to "the
only thing to use is (everything from used motor oil to the secretions from the elusive Nik Nik bug)". Which is pretty much the usual response to every post like this one. So... personally?
1. Depending on the climate (read "humidity") where
YOU live? If it's humid enough, it's likely that you will, in fact, never have to do anything to those Rosewood fretboards - except wipe them off occasionally with a damp cloth. OTOH, if you live somewhere like I did for 32 years (Las Vegas, NV - can you say "Mojave
Desert"?), treating them with something at least once a year is pretty much a necessity. Unless you
want your fretboards to look - and feel - like the wood on a 150 y/o abandoned miner's shack in the Sierra Nevadas... Since I moved to northern Indiana a couple of years ago, I've only had to put something on my Rosewood fretboards once - after a couple of winters. Probably because the basement - where they live when I'm not playing them - doesn't get very dry in the winter, like the rest of the house does. And, in the summer? Even the basement has a dehumidifier running constantly. So, yeah; it just depends on how humid it is in your place...
2. My fretboard treatment of choice for Rosewood fretboards - and every other fretboard that isn't synthetic; sealed/lacquered; or ebony? Boiled linseed oil. For Ebony? Real, from-a-health food-store, 100% Lemon Oil. Why? Because the people who made my $8200 Alembic bass - with an Ebony fretboard - said to. They made it; who am I to argue? Plus, the 5 Ebony 'boards I have, all seem to love the stuff... And, for everything else? I just wipe 'em down with a damp cloth... I've had some of my basses for... gee; going on 35 years now, and never had a problem with a fretboard - other than having to have a couple of them re-fretted (yes, their previous owner's Roto 66's...
).
3. They're your basses; use whatever works for you, and makes you happy. My bass/guitar/other stringed things - playing friends use all kinds of stuff - all of which I'm sure have been mentioned here somewhere. I can't recall any of them having any real problems with any of it (well, except for the particles of crankshaft bearings in the used motor oil that one time...
). I'd imagine the stuff you're using is just as good as anything else you can buy...
