For me, variety. Plus some razors in my opinion are better in different circumstances. There are 5/8 full hollow days and 6/8 half hollow days. I've stuck to seven or eight, balancing my RAD and my pocket, by selling on the clessifieds or donating to the giveaway. Some days I feel like a badger brush, others boar. Different scents in soaps, aftershaves etc, set a mood so for me it's really about... having fun.