Shoe Alternation: Vive la Difference?

After my last post, in which I talked about how I sprung for yet another pair of running shoes (Saucony Kinvaras) and plan to alternate days wearing them with days wearing Brooks Pure Flows, the Chronic Runner asked me a good question:

...why (Brooks) Flows and (Saucony) Kinvaras? That's like alternating green apples and red apples ;)

The argument for alternating shoes is that, because every shoe is different (even two pairs of the same make and model), alternating days wearing two or more pairs makes the shoes themselves and, more importantly, the runner's body more durable because you're shifting impact around and not pounding the same places in the feet or on up the rest of the body every time. Sort of like running on trails instead of the road uses different muscle groups and therefore makes you stronger and more durable all over.

The Pure Flows and the Kinvaras are considered "minimalist" shoes. They are very similar to each other. CR's argument: Wouldn't it be better to alternate between these minimalist models and a more traditional shoe that's really different from the two pairs I mentioned (like the Brooks Adrenalines I wore in the Houston Marathon)?

She makes a good point. But my reason for not doing this is twofold:

1) Green and red apples do taste different! Just kidding......Making the transition to the Pure Flows was easier for me than "going minimalist" has been for some people. For one thing, I'm not a heel striker. For another, because I started wearing them running on the Alter-G and doing VERY low mileage post-injury, my legs had some time to get used to them without much trauma. Nonetheless, I still experienced some of the calf pain that others talk about. It didn't last long, and now I run in them quite naturally. But I have no desire to undo the changes I made by going back to shoes with a greater heel-to-toe drop than these have--especially now that I'm doing decent miles again and have two races looming.

2) Merely making each pair of shoes last longer is enough on its own to get me to try this. The coach who suggested this to me argues that you get more than double the time with your shoes alternating two pairs than you get using the same pair every day until it wears out. If that's true, it's money in my pocket. Even though I love getting new running shoes, I don't love paying for them. I'm hoping someday to retire and maybe send my kids to college.

There is a third shoe that's occasionally in my mix. When I trail run, I'm using the Mizuno Ascends that I got through the Mezamashii Project. These are not minimalist shoes. Eventually I plan to get some minimalist shoes of some kind for trails (I'm eying the Merrell "Barefoot" line and also New Balance's version), but right now I do a lot more road running and so my dollars are following my feet.

I haven't actually started the alternating because I had to buy metatarsal pads for both pairs of shoes (I have a neuroma in my right foot and am at risk for one in my left; pregnancy left me with bunions as well as a bad back). I have the pads now, though, so as of tomorrow, the fun begins.

So all you alternators out there: are your shoes different from each other, like Chronic Runner's, or same-y like mine?