The majority of the time most photoperiod as well as most autoflowering strains require 8 weeks to flower. The exception is some of the newer fast flowering varieties that I complete a bit closer to 6 weeks.
I found that for the most part, plants take a bit longer then the breeders suggestion- the conditions we grow in- either indoors or outdoors are not as optimal as that used by the breeders. 🌱