My DP eats a lot of fresh bread which he slices himself on a wooden chopping board. He never washes the chopping board up after using it - it has a hook on it so he just hangs it up on the rack above the work surface. He doesn't bother washing up the bread knife either.
Even though the board and knife are only used for bread I still don't really like the idea of it not being washed up properly. There are small indents where the knife has gone through the wood where bacteria could lurk. Am I being unreasonable to think that they should be washed up?