Running

I think it might be time to retire my racing flats (Hyperions). You've got these, haven't you, @juanito? How old are yours?

I've just ticked over the 600k mark in them (not the one pictured), which was the arbitrary lifespan I gave them. Superficially they're not looking too shabby, even held up against a new pair I have on standby; but they fail certain tests:

1. They wobble laterally a bit when placed flat on the ground (without my feet in them).
   
2. I think they're starting to feel a little wooden (not that there's much midsole to compress in a racing flat).
   
3. The past few occasions I've worn them, my achilles tendinosis has been aggravated (though all manner of things set it off).
   
   

Seeing as I have another pair, the sensible thing would be to try them out. No perceivable difference walking around indoors, but that counts for shit really.

Anyone else have experience of racing flats and their longevity?