It depends how often you shave and how many shaves you get from a blade. 100 blades should EASILY be enough. Like Gary the numbers man says, it depends on the type of soap too. Harder, triple milled are very hard to kill. Soaps like Tabac, PdP, MdC last forever. Softer soaps not so much.So thinking of going for the 2020 challenge, what sort of quantities do you need for a years shaving? Couple of soaps, 100 blades! Still in my first six months so not actually used up any soaps yet or settled on a razor or blade type.