Like anything else that would depend on the temps while it has been stored. Does it have that lovely Liquid Karma smell? I bet as long as it did not see constant 90-100 + all is well depending on the smell just like dad used to say.
I'll go give it a whiff right now, but chances are that it smells just like it did when I got it since it has been in pretty optimal storage conditions (basement). One thing is for sure. If I am fortunate enough to be able to be in a position to use the stuff, it sure as hell can not be doing a half ass job, but life would be alot easier if it was as good as the day I bought it.