I'm in my early fifties, medium build, and flat footed. My knees aren't in the best shape, either - my right knee is extremely sensitive to rotational torque (twist of foot == pain!). I need to keep my gait square or else I'll spin out into the weeds fast.  In other words, I'm a case.  Can a shoe fix these problems?  Well, not completely - but the GEL-Kayano 17 gives massive support without weighing a ton.  Very comfortable shoe, too - I've extended my daily runs by 30%, and knocked almost a minute off my pace.  If you need support, this shoe is a cost-effective & very comfortable solution.  The asymmetric laces make me smile, too - not sure why, they just look a bit off-beat... Recommended - by an old guy with bad knees.  Will probably work wonders for runners who have fewer issues, too.