I did this once, and it took quite a long time to recover. I had a very high-paying, fun, and relatively easy job for years, but in that job I was not learning any new skills, tools, etc. Then one day when talking with some dev friends, I realized that not only was I just not keeping up with things, my skills as a developer were actually getting actively worse.<p>So I had to quit as an act of professional self-preservation. It took years to catch back up again, but in hindsight, leaving that job was the best thing I could have done. I should have done it years before I did.