bigslick, you should read cannabis Defoliation Tutorial: how to increase yeild by removing leaves. lots of info and pics there. Theres lots of different reasons to defoliate..but dont just start cutting big leaves..I think Nebula says..leaves are important, if their covering a bud site, try and tuck them out of the way I check my plants often and(unless their causing problems) just push the big leaves down and out of the way)..I have defoliated twice thru veg and once early into flower. Just trimmed a few more leaves that were just blocking light down thru the plant. Im growing indoors, with really heavy LST from early growth so the plants were really thick and bushy all thru Veg and even into flower.