Well, you pretty much answered your own question (at least as well as it can be). There is no standard because some people grow a few plants at a time while others do perpetual harvests. If you are looking to maximize your harvests, set up a SOG or ScROG. You can harvest perpetually (depending on how you rotate) every 4-10 weeks. My friend uses a SOG setup with him pulling half of his flowering room every 4 weeks (and replacing them with fresh clones from vegetative). In about a square meter, he pulls about 10-12oz each month.