How does an SSD die? It seems like traditional HDDs will drop sectors, and act quirky, but give some warning. Does an SSD do this, or just die all at once?
It usually just dies all at once. The weird thing is though they sometimes can just come back if you keep rebooting. If you're lucky, you can get the data off before it goes off again.
Even HDD's can do the same under load. HDD's can be a little tricky because they might work fine under a light load but if you put a heavy load like a backup/migration, they can crap out. We follow a different procedure when migrating systems that are more than 5 years old.