Same here. I write it on the calendar just so I have an idea. I've been growing the same strain for awhile now and they're always ready around the same time so I can pretty much know when they'll be ready looking at the date. But of course they're done when they're done. I like to know how many weeks it's been so I can compare what I think works and smokes best. I've chopped at 8, 9, and 10 weeks to experiment.I usually dont flip until I see pre flowers,so the clock starts the day I flip.Doesnt really matter though, there done when there done.