I had a supervisor who I worked with at two different companies (he recruited me to the second one). On his resume, he switched jobs every 2 - 3 years like clockwork. Each time with a raise and generally with a title increase.

His actions hurt me when he left a year after he pulled me to that new company, but, honestly, I couldn't fault him. He wanted something different, and he went after it.

I can't say I'd jump that often, but it did help me realize that the 30+ year career at one company was more than dead.