I keep mine in the fridge and have never had a problem well past its date.  Well, I never actually look at the date so I am not absolutely sure but my current bottle is several years old and I used some a couple of weeks ago without issue.  I do give it Dave's sniff test every now and then.  

--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.