USB drive on server?

[Timothy Murphy]

I'm thinking of using a USB flash disk in place of a hard disk
on a rarely used server.

This seems to be widely touted as a possibility.
But on the other hand I have been warned by several people
that the USB drive will get exhausted quite soon.

I've been unable to find any hard figures on this.

Also, I wonder if there is any reasonably standard way
of organising Fedora/Linux so that the "hard drive"
is written to as little as possible,
presumably using RAM instead.