[account42]

Unfortunately you can't set DNS TTL arbitrarily high (or low) without some resolvers ignoring your suggestion and using arbitrary values.

[Arnt]

Most historical outages lasted minutes or hours. One arguably lasted much longer, when someone lost control of their servers due to civil war.

I haven't followed this closely, but have there been any... shall we say plain outages longer than six hours? That's not an outrageous TTL. Or a day.