Someone landed on this blog after searching for: lifetime of a shoe
I am intrigued as to not only the answer to the question but also why they needed to know. Perhaps they had recently bought a shoe and it has broken or worn very quickly or perhaps they own just a shoe - just one and they don't know how long to keep it whilst they wait for the right one to come along. Maybe they have some old shoes but want to know how long you should keep them before they die and have to be sent to the wheelie bin. Or, maybe someone is making a new shoe, one that lasts a lifetime, one that is like no other.
Who knows eh?