I agree with Eric, stick with what works. I get into a frenzy when my shoes get discontinued. I'm extremely loyal and hate change (well, like every male wouldn't complain about a few women in my bed, but my wife wouldn't like that change at all!
) If a pair of shoes work, and feel great why risk change? Besides at over $100, it's an expensive gamble. Moreover, I consider staying injury free the most important thing, and a new pair of shoes can throw you out of whack.
Once we are on the topic...
Buy your car, and don't lease it. Nobody needs a new car every few years. Buy a great car, and you should enjoy it as much at year 6 as year 1. I'm still driving a 1996 Audi, and have no plans on selling. If I leased a Kia or a hyundai since 1996, it would have cost me more, I'de be getting stuck in the snow, and I'de never love my car. The only benefit to leasing is that at least my car would be clean every few years