When I started running longer distances to train for marathons, I ran into lots of other runners that iced after running say 10 miles. I did this too, but as time passed I got too lazy to pack up some ice to use at the end of long runs because these were always scheduled in the very early mornings at sometimes distant but interesting locations.

What I discovered was that cold did feel good and did alleviate some of the discomfort from running, but for overuse induced discomfort it wasn't overall helpful to me.

Now a bit off-topic to explain what did help me with overlong runs:

What helped me the most for the wear and tear caused by long runs was getting the right shoes: some would make the lateral (furthest from the midline of my body) sides of my knees hurt, some would make the medial (closest to midline) sides of my knees hurt and when I found the right ones my knees didn't hurt. Shoes without enough padding under the ball of my foot also ended up causing me more pain than shoes with more padding.

I always alternated my runs between shoes from two different manufacturers because I found that the slight differences in the ways the shoes flexed prevented overuse injuries from running in the same shoes each day.

Finally, for some reason I would curl my toes down as I got tired and bruise a couple of my toenails. I fixed this with little soft silicon toe sleeves that I could pick up at the pharmacy.