Check the trichromes' coloring every day. A fairly decent jeweler's loop helps. Mine is 30x & got it off Ebay cheap. They will go clear, to milky then to amber. Depending on the strain you've got going, you can actually influence your buzz by watching the trichromes closely. Harvesting just as trichromes are turning amber yields more of a social, trippy, high buzz. Harvesting later and later the buzz moves more & more to a couch locked stoned.