When I purchased my FW in 2005 it had Marathons on it. They did great for five years and then I had three blowouts on one 600 mile trip. I bought new marathons and two of them lasted a year and less than 10,000 miles.
I had covers on the tires, so I don't think it was caused by UV exposure. I suspect that the new Marathons aren't as good as the older ones and that storing the FW with the weight on the tires was what cause them to go bad. I plan on putting Michelins on before I take my next long trip.