can i change substrate?

without stressing my bp? It is time for me to clean and whatnot, and I want to switch from cypress mulch to aspen

Sure, you can switch the bedding, just give him a few days to adjust to it. ;)

I've switched from Repti-Bark (when I only had one BP) to Aspen (when I got more than one BP) to paper, now that I'm using a rack system. Never seemed to stress them out too much. I always give them a settling in period after I make a change like that.