I came across this link on the BMW forums. Please make sure that you check yours as well. This is especially for people like me who don't ride agressively and the tires last a long time. According to the findings, a tire's usefull life isn't only the amount of tread, but the age of the rubber.
My vehicles are fine, but I checked my CBR600 and the tires are 2001. I guess I'll be getting new tires for the 2009.