Security token questions

I've had my token since day one, version one and I have a few questions:

1. How long can I expect the battery to last?
2. Can the battery be replaced, or do I buy a new token?
3. How long will it take to get a new token (should I preemptively purchase one in preparation for when this one fails)?

Those batteries last a stupidly long time. My WoW one, which I got probably 5-6 years ago, still works now.