How often should you replace your trainers?

[truthseeker]

I wear mine (asics) for at least a couple of hours a day, cycle to and from work in them, wear them in the evenings to go for a walk, at the weekends for hill walking etc..
Sometimes I could wear them for 4 or 5 hours in a day.
So they get quite a bit of use - they look pretty old now but the soles arent worn down too much and the insides are worn looking, but not worn out. Ive had them about a year.

Just wondering how often is right to change them?

 

[NorfBank]

Around 400 miles for a normal runner.
The midsole of the shoe (the cushioning) will break down before the outer sole so even though the soles are not worn down, the support may be.
Your best option is to visit a shop, try on the same pair, if there is a noticeable difference then you know it's time for a change.

To make your shoes last longer, you should rotate two pairs, 24 hours rest will allow the midsole to regain it's shape.

I change my running shoes once a year or every 400 miles whichever is sooner.
The midsole will break down over time even if kept in the box and never worn.

 

[runner]

I do about 1000miles per asics pair (running) without any harm.
If mainly walking I suspect you could do likewise.