Hamilton Co. Vault door, from a bank demolition a friend was working on.

From what I understand, they get re-keyed, refurbished and resold. I suppose it's not like they really break down, so they just need their locks updated to be exactly as effective as they were for the previous hundred years (or however long)

I did commercial demolition for a little while when I was younger. It's fun for about 5 minutes. Then it's non-stop hard labor the rest of the time. You go home as dirty as if you rolled around in the town landfill, you're cut up, hot, bruised, and tired. It did pay pretty well for my age, and it kept me strong, so there was that. It also made beer taste amazing after a hard day of work.

vault demo is one of the toughest jobs out there.

they use super hard concrete that's extremely reinforced - rebar crisscrossing every few inches - in many cases it's more expensive to demolish so they often remove the vault doors and cut whatever holes are needed, because actual destruction takes AGES even with heavy machinery.