For the distances I'm shooting at I never use one. My groups stay within 2" out to 40 yards so I'm happy. If I was serious into target archery competitions I'm sure I would but for hunting I'll pass. I get confused easy enough now when a buck walks by. I can see it now...7 o'clock opening day a 10 point walks out. stand up...draw bow...center sites in peep site....square off shoulders...take deep breath and exhale slowly....check sight level....bow is off so make adjustment....take another deep breath....adjust sight level one more time....take final deep breath....watch as deer slips away, get light headed and fall out of stand.