Does putting knives in a wooden block blade down wear out the blade?
Wooden blocks are ideal for knife storage because they keep the blades dry (the wood absorbs some of the humidity in the air), preventing rusting. 

The motion of inserting and withdrawing blades over wood will not noticeably dull them, because you're not actually cutting the wood or indeed even applying any pressure as you do so.

A good tip is to use a good quality steel to sharpen your knives with just one or two passes on each side before each use. Wash them with hot water by hand, avoiding dishwashers unless you like replacing your knives annually, then return them to the block once they're fully dried.