I don’t use my wooden chopping boards for cutting meat any more I use the polyethylene plastic. I do use my big chunky wooden one and I have a bamboo set of 3 chopping boards for everything else. They always get a good scrub with the non stick frypan scratchy cleaning pads in hot soapy water. A couple of times a year I also give them a good oil.
After a good scrubbing the night before, so they have plenty of time to dry, I just pour on a tablespoon or so of vegetable or olive oil and rub over with my fingers covering the whole board, repeat on the other side. I stand them on their ends and let the oil soak in for about 10 mins or so, then wipe of the excess with paper towel.
It depends on how you store your boards really has to how long you leave them. Mine are stored on end as they are thick wood. My bamboo ones are in their own little stand of 3 sizes. Watch when you oil the bamboo board the first time or two, as I find they can give you very fine splinters until worn in, the option is to oil with paper towel.
I do have a big granite board that is always down flat, it’s used constantly on the bench for the hot stuff off the stove or from the oven or cold pastry. It does get used for a cutting board but I find it dulls the blade of the knife, saying that I’m glad it is used for cutting rather than cutting on the bench top, what can I say … boys!