I personally get into a HOT TUB each night just prior to bed and I put 3 squirts on my head. Before that, I used a bathtub or shower and only sprayed my temples maybe an average of once a week or basically 8 ounces lasted me a year and still probably using about 8 ounces a year.
my wife seems to be using about 16 ounces a year. I kept changing the formula based on what she liked and today we just call it adult topknot, because she liked allot of circulation...she would at times spray her entire scalp and it would glow reddish with blood circulating to the top...because she has used allot, her hair went from a reddish to a blondish.....she never had reddish hair in her life, but after the first year, her hair thickened and turned blondish, the color of her younger years before it turned dark brown.