Are you ok with eating salad dressing after the expiration date?

I bought some salad dressing recently because it was on sale. I usually check the expiration date because if they are on sale, sometimes it is because their shelf life is nearing its end. Anyway, I didn’t and I just noticed that they expire in May of 2009. Now, we go through alot of dressing, but probably not as much as we have. So, are you ok with eating dressing after it expires? Especially since they won’t have been open for very long, it’s not like they’ve been sitting in my fridge open for a year. How long do you think they are good for?