agrams said:
+1 to that. Organic oils can sometimes go bad. I have not had it happen myself, bit have heard of it happening, and it starts to put a bad/sour smell off from the board.
Mineral oils may indeed be better, but Extra Virgin Olive Oil has a long shelf life opened and doesn't go rancid like other oils. At least not in the 2-3 year time frame. However, anything that needs to be kept in a cold and dark place would definitely fit within what you're talking about here.
I've had a Walmart board for several years, haven't oiled it at all, and it is fine. Used it yesterday. It might have to do as much with the humidity level of your house or where it is stored.