thricoems (gee i can't spell that lol) anyway.. how far? you mean if leaves look red/brown, that means thc is going away.. along with buds around it...
if seeds matures, you are on the peak of high thc you can get... cuz if u harvest it late will benfit less thc!!.. but if you growing with no seeds, u got high potent of thc, so if it turn red/brownish on fan leaves, go ahead cut it..