does anyone have any good tips on how to identify when running shoes need to be changed, or a website that provides some good points?

also, is it alright to wear old running shoes for casual wear after they are no longer fit for running, or will this be harmful?

while individuals vary, I think you'll find many change after doing 500 miles. Having settled on shoes I like I cycle through, having a pair used for races and a pair for training. When my training shoes reach 500 miles they become everyday wear, race shoes drop down to training, and get new racing shoes.

__________________
Don

Having bought an identical pair of shoes after 450 ish miles, I ran up the road in one of each (one old, one new), the difference was amazing. You get too used to the old ones, they get very comfortable, the support and cushioning breaks down and you don't always notice until you try some new ones. So make sure you don't leave it too long!

My wallet is always on a diet .... so when bits of sole start to come off I start thinking about changing shoes... And then probably take another two months to do so.

The important thing is that you still get comfort/stability/safety from your shoes. When you start losing grip, feeling uncomfortable, toes sticking out, it's time to visit the shop.

__________________
“To give anything less than your best is to sacrifice the gift.”

I rarely seem to get more than about 350 miles out of my shoes before the cushioning goes in them. But I am a bit of a big lad, so my 350 is probably worth about 500 of anyone elses!

I like the idea of wearing one new and one old shoe to compare the difference. I'll try that!

Like BP said, I could not belive how much cushioning my old pair had lost when I bough a new pair of running shoes - definately make sure you don't keep them too long.

500 miles for me.

Crikey Dave, thought I was on The Great Wall of China Thread!!

My shoes cost me 80 pound.

I have run over 500 miles in them, but I find it hard to force myself to buy some new ones because they look brand new.

Will do on pay day tho.

I felt exactly the same buying my new ones, and truth be told I can't tell that much difference changing from one pair to the other... perhaps I should do the "one on each foot" comparison!