I bought a HUGE bottle of this along with the matching Shampoo (1000 mL / 33.8 fl oz) and it literally lasted me for 3 years. This is a great shampoo that leaves your hair looking healthy and shiny, but I got SO SICK of using it after a year. Even though I got it for a great deal ($25 for the whole bottle), I would recommend buying a smaller size if you're the only one using it. I like to switch up my shampoo/conditioner once in a while, and this bottle was just too big for me to buy/invest in other new conditioners.