This piston is out of my '06 at just over 300 hours of desert racing, a bit of MX, and general rec riding. It really should have been replaced a little sooner, but there was no harm done, and the bore was in very good condition.
The areas of concern to me here were the fact that the wear shows the piston tilting in the bore excessively as indicated by the bright stripe along the bottom of the rear skirt, and the drag marks on the ring lands on the front side (arrows). The ring lands are never supposed to contact the bore walls at all, so it was past time to switch it out, actually.
An often overlooked area when considering the reuse of a piston is the ring grooves. The grooves tend to wear a little wider at the outside than they do farther in, which lets the ring twist out of square with the bore, affecting wear at the ends of the ring sweep where the rings reverse direction, and sealing in general. Measure the ring groove clearance carefully with this in mind.