It's pretty simple. When you want to know the right time you need to get tiny. Just looking at the plant doesn't really tell you much, not even rusty pistils.

Get yourself a 60x jewelers microscope off eBay for $5. you can keep a good eye on the development of the trichomes. It's the most accurate way.

Im growing big bud x northern light cross right now and I'm in week 11 of bloom and I still dont see amber/rusty trichomes. It's all about being patient.

They go from clear, to milky to rusty. If you like a energetic, uplifting high then harvest when you see 10 - 20% amber trichomes. I you like couchlock then wait for 70 - 80% rusty.

When trichomes are clear the trichs are a little premature. when cloudy they have a good THC content. Amber is the signal that the THC is breaking down into CBD.

I mix of CBD is good with THC. Just depends on the high you like. I will wait for 30 - 40% amber.

The 60x microscope is vital.

Hope this helps. The guys added some great info on this thread too.

Take care