If they aren't ripe, you are wasting a lot of potential. First, you have to determine what the qualities you are after of a particular sample; do you like that "electric" feeling that some give you, or are you more a fan of the dopey, dreamy effect? The earlier harvest typically provides the first, and the later harvest, the second. I far preferred the second.
You might be able to use a large magnifying glass, but I much preferred a small, hand-held microscope. If the trichomes are pointy, that's pretty early, at least for me. When they develop little bulbous "heads", they are getting ready for harvest, and when those capitate trichomes turn milky or a light tan colour, they are really ready.
They are pretty hardy, especially the Indica variety, but definitely don't let them freeze. In fact, don't store even your dried bud in a freezer - cool, dark and dry is the best environment for drying, then storage. Many of those strains are from the mountains of Afghanistan, for example, and it's not exactly a tropical getaway.
Best of luck! I kinda miss those days of my past, but I don't use it myself any more, and there is little money in it because of legalization.
I apologize if I've told you a bunch of info you already know, but it's better than not knowing. Best of luck with your endeavour!
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