I personally use a small pair of scissors, tweezers and a hand held microscope to take small cuttings from a bud and look at them for trichome development. I used to try to look at the buds on the plant, but I'd just end up mauling the bud. So I started cutting little pieces off (I mean little, most cuttings are smaller the the "&" symbol on my keyboard) once a week starting from about week 6 or 7 of flowering. I look for between 25% and 50% amber trichomes depending on if I want a more mental or physical high. The more amber you see, the more couch lock the buds will induce. If you want something to lay you out for a nap, cut at more than 50% but don't let it go too long (not more than 80% I'd say) or you may miss the peak of ripeness and see a drop off in quality. Also some strains, I have been told never produce amber trichomes, in these cases some people recommend looking at pistil development, others simply say you kind of have to just feel it out. I have never dealt with a strain like this so I can't say from personal experience.
Thats how I check too. I've stayed pretty much with a couple of strains now and know when to chop...usually a combination of the microscope exam (tri-chromes) and number of red hairs. My fav is maybe 20 or 30 percent amber tc with the red stamens about the same...thats for white widow...
very few pistils are starting to brown if the Ch9 bumf is correct should be cut around day 50(next sunday)! just dont look that ready yet i'll try a microscope tonight as there sleeping just now. will update later on tonight. cheers people!