I've got 31,000 kilometers on my Metzler 880's front and back. The rear has what would be acceptable wear and should be good for one more season. The front is showing signs of cupping but has a lot of tread left.
My bike has just started showing it's first signs of front end wobble when I take my hands off the handlebars. Used to be rock steady. I'll probably change the front out next year with the rear and check the headstock bearings.