I'm too young to have grey hair but I started having them when I was 18 so I prematurely started having grey hair. I use dyes like these every few months to keep the grey hair at bay. The products come in squeeze tubes so it is easy for me to measure out the small amount I need for covering my grey hair. This should last me a long time. I tried it out and it was fairly easy to use. Only time will tell how long it lasts.