Could it be so simple?

Last time I talked about my knee problems, and how it was preventing me from running any real distance or on hard surfaces.
Last week, after installing a ceiling light fixture in my basement, doing a lot of stretching but not much knee bending, my knees did hurt me. In addition, I was having a small amount of foot pain; something I have not had for a while. The last time I had this foot pain, the problem turned out to be worn out Superfeet insoles.
I switched the insoles, but this time it made no difference. I still had the foot pain, even while just walking or standing.

I started thinking about shoes again. For a very long time, I have been using my old running shoes with 400+ miles on them for everything outside of running. I had given some thought to this before, but I never had an issue with pain before, so I dismissed it.
Could I be hurting myself by wearing these old, worn out shoes?
My reasoning had been that I don't need the support I get from my running shoes while I'm not running. I thought it was OK to wear these old shoes around the house and anywhere I go that doesn't involve running.

I decided to try an experiment.
I took off the old worn out shoes, and put on my running shoes, with only 100 miles on them.
I could immediately feel the difference in support, and by the end of the day I was convinced that the shoes were the difference. My foot pain had gone away.

I didn't run for two more days, allowing my knees to recover. The next run I did was on Saturday, on the track. I ran pretty hard, 5 miles, and had no pain.
For running, I was wearing a nearly bran-new pair of Mizuno Wave Alchemy 7 that had only about 20 miles.

On Monday, I ran on the treadmill, again a moderate run, and had no pain.
I stopped having the pain on days off, and when I climbed or descended stairs immediately after running.

I did another run of 5 miles yesterday afternoon on the track, and once again, no pain whatsoever.
So, it looks (actually, it feels) like the shoes I wear for non-running are just as important as the ones i wear to run.
Since I was now wearing my Saucony Grid Stabil shoes for walking, I ordered another pair of Mizuno Wave Alchemy, now model 8, so I still have two pair of running shoes.

I hope that this finding proves to be correct, and that my knee pain will stay away, to allow me to build my mileage, and train for the New Jersey Marathon next May.
It's a shame that I had to experience pain and sacrifice my running before I would try something so simple as changing shoes, but that seems to be human nature. You don't fix what ain't broke.

Today is a day off, and I am taking tomorrow off as well, as I will be going into NYC to spectate the ING NYC Marathon for the first time ever. I have run the past 4 NYC Marathons, so it's going to feel a bit strange to be watching this one.