One of the local running clubs actually recylces them. I think they send them out to third world countries. I need to retire a pair as I've noticed my knees, glutes, back really start to ache when I run in them.
Ive not got through my first pair yet, how long should i use them for before changing them? There was a women in the shop when i bought mine that had her running shoes for five years and she was very reluctant to get new ones.
Generally you should change your running shoes about every 300-500 miles. You generally know when they are starting to go as they loose all their bounce and you get a few more niggles than before. If you run about 20 miles a week then a pair of shoes may last you 15 weeks or so (based on the lower end).