I started smoking pot (and reading Castaneda) at age 17, now I'm 54. That makes 37 years. My previous harvest was in 2001 of 40 oz of Burmese X Fuckin'Incredible, which took 5 to 10 tokes for a good high. I was averaging 5 oz per year for 6 years. That harvest has lasted longer than 6 years and I quit smoking it (still about 10 oz left in my freezer) because it is lousy compared to my last harvest of 13 oz. This super-stuff should last about 2.5 oz per year. A little math says this should last me another 5 years, since I'm the only one that smokes it.

I think the key is letting the plants flower extra long, for extra potency.