Some folks have a different board for everything. But I’m a minimalist, I don’t have a lot of space, and less is always more for me. (I do make an exception for raw meats. They have a cutting board all to themselves.)
The trouble comes when:
There are two ways I keep my board in odor free condition.
The first is white vinegar. After use, I pour a little white vinegar on the board and give it a scrub. Vinegar is a natural disinfectant which gives me peace of mind.
But if the smell of onion is lingering… I sprinkle the whole board with baking soda and let it sit for about 10 minutes. Then I scrub it in with a clean soapy cloth. It makes a sort of a paste as I scrub. Rinse the whole board and VOILA the board is odor free.
I’ve used this same board happily for many years. With just a little maintenance my onions and pears can live happily ever after on the same board for many more years to come.