I have some Bamboo slats (25) I bought over a year ago. keep them in the house under the bed. Will they dry out and become brittle in time. I have used them on 6 bows, one blew up and another one raised a splinter in the bamboo after several months of shooting, the other 4 turned out great.

I don't think they age, but they can get eaten by bugs.  One of my thickest poles was riddled with pinholes from a tiny beetle. You also have to watch out for overdryness, but that can happen at any age.