Depends, what is the flooring like in the room where the critters are? If it's carpet, try for the tiny pieces (believe me, I've used the large shavings and shredded aspen, and getting that out of carpet is worse than hell, plus you cannot vacuum the large stuff of you'll spend more time unclogging the vacuum than actually cleaning the floor), if it's linoleum or tile or similar, I'd go for the thin curly shavings, because IMO, I'd say it absorbs the best, and would be the most cost-effective, as well as the most comfy for the critters.