I have 3 or 4 plastic & one wooden.

The wooden one I find I use more for sandwiches or for hot pots etc. The plastic I use for everything. Mine get washed up with the dishes as I go.
If for some reason they look off colour (I had one that used too all the time for some reason) I will bleach. I have only had that problem with that one though.

I know all the rules & never mix foods & they all get a good scrub between uses.

I worked in a cafe for years & we had all the colours for the different foods. I've though about doing this at home, but without that volume of food being cut up, I don't think its needed. Even though I am now cooking for work.