They should last longer then a year. store them in a ziplock, bag.
SHOULD last longer then a year, but shit happens. u never know. so make sure to take tons of spore prints!
even if u dont know how to turn a spore print into a syringe, take spore prints anyway, and when your ready to take that step, you will have something to work with.
wait till the veil begins to tear away from the cap, cut the cap off, and lay it on a rectangle piece of foil, with a cup over it, (i use plastic disposable.) but prop the cup up on a nickle that way there is a small beather hole, so that humidity, can escape. (if not you will come back to a slimy mess) then leave it there for 24 hours. then carfully lift up the cap off the foil. and fold the foil over on itself, and around the edges, to make a protected packet. label that packet with the date, and the strain. then place it in a ziplock bag. it will keep for years. then u can still take the cap u used, and dry it. YOU HAVE NOTHING TO LOSE, AND EVERYTHING TO GAIN!