Burn... you do realize that this thread (other than your post) hasn't been posted on for almost 7 years... right?
A good thread, and worthy of reviving, but a lot of the previous posters haven't been on here for a long, long time.
Just saying...
We haven't looked at any of our kits for a couple years... but that's because of our move.
Before that we used to check them annually (should be every 6 months, but we just never got to it like we should've).