That's how long it takes for a guy with little to no hair to go through a bottle of shampoo, and by "a guy" I mean "me." Yes, I finally finished off the bottle of coconut shampoo I bought after my first trip to Hawai'i over 16 months ago.
When you have so little hair that next to no shampoo is all you need, the bottle tends to last a while. I started shaving my head about three years ago and in that time, I've gone through only two bottles of shampoo. The annoying thing is that I tend to go through shampoo so slowly that the shampoo I buy tends to vanish by the time I need another bottle.
Apparently the rate of change in the shampoo industry is faster than my rate of consumption.