In reply to Alex_Handhold:
I get anything from 200 to 1000 miles from shoes, occasionally even more if I like a pair and it holds up, like the Salming Miles I have just retired.
I have several pairs on the go at any one time, but don't rotate them as much as I probably should. I just wear the pairs I like best most of the time.
It's always the uppers that limit the life of a shoe for me.
I also find that, unless a shoe goes by getting a really long slit along the side, like my TopoFlyLytes, I can usually still use it with holes in for quite a while, and might use it as a walking shoe before I finally stop using it. A very old pair of Roclites are my allotment wear for when it is muddy, and an old pair of Adrenalines are my painting and decorating shoes.