Check out http://www.adultclothdiaper.com/Plastic-Pant-Care.html
for some hints on how to care for them & make them last.
Some hints from me, for those who don't have the luxury of perfect privacy:
Rinse your pants out while you shower. Pat them dry inside and out, and hang them on a pants hanger. Take another regular hanger with a baggy shirt, and place the diaper hanger inside the shirt. No one will notice that you have 2 hangers sticking out of one shirt.
Accept the fact that plastic pants will begin to smell like stale pee over time. You can reduce this by machine washing and using tons of bleach, but you will never completely eliminate the smell and you will drastically reduce the lifespan of your pants.
Try keeping them in a sealed container like a Rubbermaid tub and/or keeping them in a closet with a time-release deodorizer, just a little something to cloak the smell. Everyone's bedroom can smell a bit funky from time to time, so don't worry about the smell- it's no big deal, and no one will notice.
P.S. Now you gotta get some thin plastic pants, like the regular Leakmaster/Gary product. Totally different experience!