I put replacement blades in my Muzzy's every year. I carry 3 arrows in the quiver and after a season of being in the quiver, vibrating against the foam on the atv ride in and out, plus the first arrow being pulled out and replaced several times, they are definitely duller than when first put on the head. I keep meaning to look into a sharpener but haven't remembered to get one yet. Think about when your shaving...if you cut yourself with a dull razor you've been using for a while, it takes nothing to get it to stop bleeding. But cut yourself with a new sharp razor and it takes forever to get that sucker to stop. The more it cleanly cuts, the harder for it to clot.