Why do you own more than one razor?
Collecting double-edge razors is a hobby more than a necessity. There is no functional reason to have more than one. A quality double-edge razor, such as a Merkur HD, is not susceptible to wear and tear, and will provide you with years of great shaves as long as you clean and store it properly. Part of what makes my daily shave enjoyable is having the option to choose from a selection of nice razors. If you're not a collector, however, your shaving experience can be equally enjoyable if you have one good razor that you love.