I use these as spring/summer/fall tires (I use all-season because we often get freak snow in Oct/Nov & Apr/May). In two years, I've put a little under 30k miles, almost 80% hwy miles, and they are down to 2/32 tread. If I was truly using these as all-seasons, then they would have needed to be replaced long ago.
When they were new, I loved them for the first summer (May thru Nov) -- quiet, great wet road/dry road balance and good responsiveness. When I put them on this spring, I quickly fell out of love about 2 mths into the summer as they did not have the same wet performance and grew louder.
The only reason they're still on the car is that we have had an exceptionally dry summer and I was hoping they would last until the winter wheels went back on, but after driving them in the rain yesterday, I know that's not going to happen and I need to replace them immediately.
Hopefully I can find something that will last a little longer this time...