How long do new receiving addresses last?

[gcgipson]

When I generate new receive addresses, and I do not actually use them, how long do these unused receiving addresses last?

[TierNolan]

They last forever.

It is recommended that you use each address only once, but if someone sends using the same address a few times, you still get that money.

You shouldn't generate to many addresses in sequence though.  If you do, then using a backup might miss them.

Each seed can generate an unlimited number of addresses, but Armory only actually checks the first 1000.   If you received money for address 1,000,000, then Armory wouldn't know about it.   You would have to specifically tell it to generate more addresses when restoring from backup.