My patches come in foil wrapping, so I store the unused part of the patch inside that and tape it closed. I'm pretty sure it still loses effectiveness over time (after opening), but the remaining sub-patches still have (quite noticeable) alertness effects.
Hm. Maybe I should try out patches. (After my nicotine/DNB experiment, I'll be pretty low on gum.)
http://theviewfromhell.blogspot.com/2012/09/toward-non-stupid-non-blank-slatey.html
The author gives a shout out to Less Wrong as a community with a perpetually skewed gender ratio, which is precisely the conditions under which polyandry appears to thrive.
Discuss. :)