A good general rule of thumb for harvesting is 85% of the trichomes milky, 10% amber and 5% clear.
Clear Trichomes do not give the best psychoactive effects
Milky Trichomes are the most potent ones on the plant
Amber Trichomes have actually degraded and THC is becoming CBN
There is a short window where Trichomes go from clear to milky to amber