It is all a matter of preference.. the breeder tells you the effects of their strain when harvested at 100% cloudy, no amber... SOME people like a more couch-lock, so they allow a few to START to go amber before harvest to raise the ratio of CBD to THC.....
As long as they are cloudy, headed up and not clear-- she's ready to go when you are!
But Like the little bearded trouser-troll guy said-- the more they go amber- the more they degrade!