Oh, I didn't see your post Robin but thank you as well. Although I use aspen shavings over care fresh/critter care stuff for all my rodents (feeders and pets) because I find that care fresh gets terribly dirty and sometimes even moldy EXTREMELY quickly I mean in less than 3 days or so... I had to change the bedding almost every day. I just prefer aspen because for my animals that don't make a whole lot of mess when they potty (my mice and hamsters) I clean it maybe once a week or two times, same as my big potty makers like my pet rats (and eventually feeder rats). Only thing I don't use it for is rabbits, they're just so messy lol.
Although you're right about rats & mice being prone to respiratory disease, aspen shavings aren't as bad as a lot of people may say they are; the only time I've had problems with excess dust is at the bottom of the bag, which I just trash anyways to avoid the risk. I've owned a lot of rats before but have always found aspen my favorite bedding to use, it's fairly cheap around here too