I had a bottle of Clean Shot that was over 6 years old. I just finished it off. It shot as well on the last shots as it did the first. I have a bottle of Triple Se7en and it must be pushing two years old I am still ocassionally shooting off of. Like you, I store it in the original bottle in nothing special. I shot some of it a few weeks ago and it was fine.

This just means you have to make up reasons to go out and shoot more.. No sense wasting the stuff..