I'm on four.

I quit my job today. Over the last three years I've

a) been given redundancy notice. then got another job I'd been ring-fenced for so was kept on.
b) quit to do further study. Got re-employed in a better job one year later.
c) quit to go freelance Got asked to come back two months later to cover staff shortages.
d) quit again today now shortages are covered.

Have you ever worked in the same place multiple times. Cool thread, huh?