Sadly, I don't seem to ride enough to wear tires to the point of thinking about whether to rotate them. That, and my tires are large for my weight (narrowest are 28mm for a 155 lb rider) so they take even longer to wear out.

The only time I've been presented with this choice so far, I had 4 years or so on the tires (5000+ miles), and was ready for something else.