I'm with you Daytona - I don't know how people get the milage out of tyres that they do.
The best I've managed out of a rear tyre is 12,000km (7,400 miles) from the original Macadams (90x).
From the Metzler M1 got 7000km (4,300miles), but that was really pushing it past it's use by date - realistically I only got 5000km (3100miles).
From the Metzler ZE4 I got 8000km (4900miles).
I've now gone back to Macadams (100x) on the rear, it's got 2000km on it and hardly looks used.
So I'm on my 4th rear tyres in less than 30,000km (18,600 miles). But I'm only on my 3rd front - mind you it'll be due for replacement in a few thousand K's.