when a game breaking update happens, or catastrophic failure of hardware, software, or security resulting in loss or corruption of savegame and backups

^ what they said. we only wipe the server if we are forced to.

they've only been forced by gunpoint to reset server a few times, probably not going to happen again

The map has only been reset 3 times in the server's history, and only one of those was planned. The first was during 1.8 due to an attack by a particularly malicious hacker. The second, which was planned, was for the 1.9 update due to major changes to Minecraft. The third was shortly after 1.11 released due to changing server hosts.