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The trick to getting a perfect shave? A sharp blade.

It's vital to prevent razor burn, nicks, cuts, and ingrown hairs as well as folliculitis—bacteria build up that causes pimples and irritation.

A blunt razor that scratches or pulls needs a new blade immediately. Another way to know when it's time to toss your blade is when you have to go over the same portion of skin more than once get a clean shave.

To keep skin safe, change your blade every five to seven shaves if you have light hair and every two to three shaves if you have coarse hair. My fave: Schick Hydro Silk ($10; mass retailers).

It has curve-sensing blades to help prevent careless nicks and cuts and a water-activated moisturizing serum that keeps legs extra hydrated.

To get your blade to last longer make sure to dry it after every use and avoid letting it sit and rust in the shower. Or, for about $20, The Blade Buddy helps extend the life of your razor from days to weeks by resurfacing the blade and keeping the edges sharper, longer.