[dmlittle]

If you like the people you're working with, enjoy the work you are doing, feel like you're learning and exploring new interesting/challenging problems and feel like you're being compensated fairly, I don't see a reason to switch companies. Remember there is always a risk that you won't like your next job as much as your current one (and the opposite is also true).

I'd look to change companies if any of the following, among other things, apply: you're working in a toxic environment, you don't get along with your co-workers, you aren't being challenged at your job, you aren't learning/expanding your knowledge, you aren't being compensated fairly, or you feel there aren't personal growth opportunities left at your current company.

Full disclosure, I am a recent grad so maybe I'm just being naive.