This is a very hard question to answer aaccurately. First trying to figure out how much you actually smoke a year, then you have to realize that you might not end up growing good, healthy, high yielding plants. Your always going to run into some problems- some plants might get stressed thus stunting them, some might die from various causes. I'd say estimate your yearly consumption then research different strains and growing conditions, then start more than you will need and go from there. Hope that makes sense. I started more than needed and more than I had space for and unexpectedly they are all thriving. Now I dealing with a jungle. Just can't bring myself to "thin out the herd". I'm in for the duration- lots more work than I expected, hopefully ill be rewarded come harvest.