California cannabis growers, extractors, processors, and retailers have been lab testing their products for potency and purity for at least the past decade, dating back well before Prop 64 and the implementation of recreational marijuana legalization in the state. For those with established relationships with professionally run testing facilities, these early years of practical analysis helped them to hone their craft and refine the quality of their products, giving them a very useful headstart once the industry did evolve.