How long should a tank last before you need to renew?

Something I have always been curious about when it comes to tanks that you house your fish in is how long you should keep a tank before you need to replace it. Things such as the tank becoming weak or not being able to clean it well enough I would have thought would be an indicator as to how often you need to renew your tank.

From your own personal experience, how long should a tank last before you need to renew or replace it so that it stays stable and safe for your fish?