Even that depends on what you're doing. Most scientists aren't running apps that require several 9's of availability, connect to an irreplaceable customer database, etc.

An outage, or even permanent loss of hardware, might not be a big problem if you're just running computations on data of which you have multiple copies. At worst, you might have to copy a few TB of data from an external hard drive and redo a few weeks' worth of computations.