I agree with lefty....i've been in camp for days without anything resembling a scent cover let alone a shower and have had deer with in a few yards of me. I was sitting on the ground in the brush, not in a blind and have had bucks and does come very near me.
Swearing by these cover scent products is buying into the hunting show/infomercials that tell you that you can not be a successful hunter without them....that's a load of bull.
My grandad killed untold numbers of deer and never owned a stitch of camo clothing, had never heard of cover scent and he used a .30-40 Krag or a 38-40 Winchester, neither of which ever had a scope. Of course this was before Team Realtree told everyone that you had to wear their clothes or Polaris made folks believe that a 4 wheeler is necessary to hunt deer. Their cover scent was campfire smoke, coffee or Old Crow from the night before. At one time my granddad had the biggest Pronghorn killed in TX, (this was in the 50's) he did it with iron sights and, I promise you, no cover scent.