When faced with a bunch of jars full of medicine, I focus specifically on the trichromes. A close examination will provide not only an indication of potency, but also clues as to how the marijuana has been (mis)handled. I use a 10x loupe , which works very well. I mostly ignore the genetics and look for pampered pot. I will generally still purchase medicine with some missing trichrome heads, if the trichrome density is high enough and there are no other flaws.