If properly cared for, a wooden cutting board can last a lifetime.
1] Quickly rinse off whatever is left over from cutting food. The quicker you give it a wipe, the better. Use HOT water and soap, and don't be shy.
2] Immediately dry it with paper towels or a clean cotton towel.
3] Do NOT soak/submerge wooden cutting boards, or run them through a dishwasher.
4] If you've cut something intense like garlic or onion, use some white vinegar to de-odor the board.
5] For stubborn stains, you can sprinkle baking soda on the board and work out the stain with a lemon. Make sure to rinse with hot water and dry with a clean towel. Kosher salt with lemon will also work.
1] Rub cutting board with mineral oil.
2] Use beeswax to hydrate, shine, and waterproof a cutting board.
3] You can use sandpaper (220 or higher) to re-sand and polish the board. Use mineral oil afterwards.