The following comes from Adam Hurly of Men's Health:
You want to get the most out of each blade—the closest shave, sans any agony—but it begs the question: How many shaves is too many before a blade is past its prime? And what factors contribute to its retirement? We spoke about these things with Fellipe Cardoso, barber at Otis & Finn Barbershop in New York City. He told us everything you should know about proper blade storage, and how often to switch out those blades.
Don’t just shove it in your Dopp kit after shaving
Following each use, Cardoso says to rinse the blade thoroughly under hot water with high water pressure, “until you don’t see any hairs or dead skin sitting on or between the blades.” Then, if you want the added assurance of a disinfected blade, he says to pour rubbing alcohol on a thick wash cloth, and then to wipe and sterilize the blade. “You can do this before and after use,” he says. Let it dry all day or night, upright in a razor stand, which allows airflow to every part of the blade.
Once the blade is dry, consider tucking it away in a storage case outside the bathroom. “Storing your razor in the bathroom can expose the razor to damp air, steam, and moisture coming from the shower,” says Cardoso. “Even if you’re only actually using a razor once a week, your razor will still begin to oxidize and rust from being exposed to moisture. That kind of environment will also allow bacteria to thrive on a used blade." Try Kicode Travel Razor Protector, which is, as you might have guessed, useful for protecting the blade while you travel, too. Just be sure to wash and dry the case each time you use the razor. And, again, keep the razor out of the bathroom between uses.
Replace it more often than you think
Some companies might tell you that you can use their blades as many as eight times before requiring a new blade. “I’d recommend about half of that,” Cardoso says. “Especially if you are a frequent shaver, you can usually get three to four good shaves out of a razor.” He says that razors produce diminishing returns with each shave, “so your shave will be less close with each use.” A duller blade can also give you razor burn because it will drag across the skin.
If you shave infrequently, Cardoso says you can still use the razor up to four times, but pay attention to any rusting. "The biggest risk of not replacing a razor frequently is that it will rust or become a hotbed for bacteria,” Cardoso says. “These razors are sharp and have direct contact with our skin. So, if you have even a small cut or nick, you give bacteria a direct entry into an open wound. Dirty or rusted razors could lead to a bacterial infection, or even tetanus.”
Want to save money and get the closest shave? Consider a safety razor
Cardoso swears by the double-edge safety razors for a couple reasons: First, blade replacement packs are usually affordable. Go with something like Shark’s Double-Edge Stainless Steel Blades. Second, a safety razor has a super sharp blade—one that never dulls, because you’re tossing it after a single use—and that cuts the hairs with one blade instead of three or five on other razors. This puts less pressure on the skin, and tends to cause less irritation and fewer ingrown hairs.