I think job hopping is a personal choice. Seems to work very well for some. I am personally not a big fan of that. I believe in finding a good place, and planting seeds, then seeing the seeds bloom. I spent 11 years at Microsoft, 11 years at Amazon, and now on year 2 at Google. There's some benefits you get (for example, usually a bump in compensation, learning a new culture or new technologies), but there's also a big tax to pay every time you leave a place where you've made some investments!