I'm not sure what the lifespan of a Security token is, I've had my SE security token for 3-4 years now. But I would like to suggest having the ability to add a second Security Token to an account incase you lose one, battery dies or dog eats it.
Then we wouldn't have to go through customer service to resolve the account issue. We could just log in using the functional security token, remove the old one and set up another new one if we'd like.
With resources like Security Token Apps and the number of smartphone users out there, most people have 2-3 devices around the house that can use the Security Token App. Keeping two of them attached to your account would streamline the resolution process for all the account issues that SE probably has to deal with.