I agree with organoman, but your best bet would be to check the trichomes with a magnifier or if you dont have one you can try using your mobile phone camera and zoom (depends what mobile you got). Than it's all up to personal preference, milky white trichomes you have the highest level of thc with an intense high and when they start turning amber you will have slighty less thc and get more cbn, resulting in a relax couch locking high. Hope this helps ! Happy Harvest =)