I think it has to do with what your body's used to. If you smoke primarily a indca or hybrid and you get your hands on a good sativa it can change how long you feel it. Tolerance to a certain strain or whatever chemicals in that strain can effect the length of the high. It always happens to me once i get a new bud...I get an oz of bud...,we'll say its indica for this example, smoke it for 2 weeks, and if i get a new oz of a different strain but its still indica...I feel like my tolerence is a lot higher then if i smoked sativa for two weeks and switched it to that indica. I don't know if you guys get it from smoking the same but I.E. smoke today be high for 1 hr smoke same bud tomorrow and be high for 8 but thats never happened to me before. Just a stoned though haha :rastasmoke:.