How long

Depends on the type of high you want. Regardless of terpenes and genetics if you harvest with milky thrichomes its the peak of the effects you get sedative and active high. If you wanted fully active high, harvest with clear+milky cristals. If you want it basically fully sedative, just hold on untill its fully amber crystals and you got it. I like to harvest them at a point where some might say its a premature harvest, but i know what i'm aiming for, it just blast my mind everytime, since i need to be active and can't even risk couchlock i harvest with clear crystals. I get less yield but i get the high i want, and its better to get 70% of what you like than 100% of what you don't really want. You can defenitly harvest some parts and leave the rest to mature. Stay well, and good growing growmie