My last set of Schwalbe Marathons lasted over 8000km, and would have lasted even longer if I hadn't been forced onto my trainer for a month of riding thanks to the COVID lockdown here in Shanghai this spring. Only replaced them because they'd worn down to the threads. My new set of Schwalbe Marathons that I installed in June now has more than 3000km on it and they still look good as new, so they won't need to be changed any time soon.