Also, if you don't smoke a lot and you'd like your stuff to stay fresh longer, store it in airtight jars in the freezer if at all possible in the house you live in. It'll stay fresh for up to 6 months or so at room temp in air tight jars, but heat (even fluctuations from winter room temp to summer room temp) will eventually start to degrade the resin. You'll notice that when you harvested it was all milky, but after a while it'll start to turn amber sitting in the jars. This is when you've left it too long or stored improperly.
My brother smokes a few times a year now that he has a kid, and he's kept a jar of my stuff well over a year in the freezer with nice milky white heads still. I'd freshen him up more often but I just don't get to see him all that much, so this technique works fine for him. Also, if you grow outside for personal use, the freezer method allows you to keep fresh until next season's chop.