I have three razors ('59 Fat Boy, Merkur HD, and Merkur Futur) that I like to use in my rotation depending on my mood, the day, moon phases, etc. I like to keep my shaves to three per blade and I am wondering how people keep track? I haven't found any reasonably simple methods yet (not quite ready to create a spreadsheet on my laptop ). Let me know if you have a fairly simple process to keep track. Thanks!