I can already hear my uncle-in-law saying, " you've got another new job?", as a reluctant member of gen-y, so I gots to thinking...why is it a big deal to change jobs?
If I look at a timeline of my younger days, now slowly disappearing into a memory (can you hear the tiny violins?)
How did I continually move to the next 'thing'? Because I got better at doing those things, I passed, I graduated.
So, why stop?
Now, whenever I get to that point of 'I can't learn anything more from being here - and I can't teach them anything more', then it's time for me to go.