My understanding has always been that the flowers are at their peak ripeness when the trichomes become milky with about 20% of them turning amber.
But when did this become the common ideal?
I'm pretty old and been growing off and on (mostly with no idea what I was doing, tbh) since the mid 1970's. I never knew anyone back then who had any idea about trichomes. Back then, the only way growers knew the plants were ripe was when the seeds were ripe! And those ripe seeds usually were accompanied by leaf color that was light green or yellow (gold)...sometimes reddish-brown..."Fall colors" let's say.
Growers who grow plants for smoking, don't (usually) allow their female plants to be pollinated and produce seeds. At some point in time, the milky/amber trichome formula became the ideal for determining when to harvest. My bet is that, when people determined that THC was the "psychoactive component" in marijuana, and started to test for it, they found that the milky stage was when THC levels were highest. When the milkiness changes to amber, then there is degradation in THC...Therefore, all amber trichs would produce less potent marijuana. But...Is that true? What about the other, non-tested-for components in the flowers? Do any of those increase? -flavonoids, terpenoids, volatile esters, etc.
I may be wrong, but I get the feeling that a lot of personal-use growers are using big, industrial, high-yield grow ops as a model to follow. "The guy with the biggest plants, wins". And, in doing so, the small op growers cheat themselves out of the luxury of being able to take extra time for their plants to ripen and develop more complexities and unique smells and flavors.
I can say, for sure, that whenever I scope any weed that I buy in the commercial market, the trichomes are clear.
In other words, they are underdeveloped and not ripe. And I'm not talking about some bottom-shelf shwag. I'm talking about the best stuff available in the store! This is the stuff that people buy and then review and say how great it is....But they also have to stuff their noses entirely into the jars in order to get the smell! "Piney" "Lemony", they say.
I think part of it is that the pinene and limonene terpenes develop earlier than some of the others. Maybe if those flowers were let to TRULY ripen to milky/amber or all amber, then they wouldn't be so piney or lemony anymore. But, hey, if the big producers need to meet a quota and the plants are still not ripe, then just harvest them, anyway. It' good enough.
Based on this, I don't believe it's a good idea for the personal-use ops growers to use the same criteria as the industry uses...because the industry doesn't care about putting out ripe marijuana.