Razor blades are expensive and getting more expensive with each new blade they add. The steel doesn’t get dull because of the haircutting process, but mostly from oxidation on the blades. One way to maximize the longevity of blades is to keep them dry between uses. Easier said than done!
Another even better solution is to spread a little bit of lubricating oil on the blades after each use. This is the same oil you apply to electric razors and clippers after each use. I’ve been doing this for years, and the razor blades last many times longer – months! (My electric clippers cut like new after almost ten years.)
This may seem like a picayune way to save money, but it does save resources. High-strength stainless steel uses precious resources – more so with tungsten blades. Pure tungsten does not rust but the low-quality tungsten used in razor blades can oxidize and rust over time. The stainless steel used in razor blades is low-quality, and hence prone to oxidation and rust.