Pepper spray expiration date - what's the reality?

This morning I figured out that my "Sabre Red" pepper spray (round black plastic canister) "expired" 01/2017, which is about 9 months ago. It's been in my winter coat pocket this whole time, mostly in a closet. Along with that one we have 3 more spares from the same lot still in their packages - also stored in an indoors closet. How much loss of real effectiveness are we looking at? How much of a hurry should I be in to replace them, and what would you recommend as a replacement?I like the idea of the Kimber pepper blaster, but I keep balking at the $30-$40 price tag and the 2 shot limit. But I've heard good things about them. On the other hand, a small round canister is a lot more discreet and less likely to cause trouble in backed-by-law GFZs. Which I'm required to briefly visit pretty much twice every weekday.Blow back is a concern, too. via /r/CCW http://ift.tt/2yfXV8Z