It appears you are talking about a MAJOR shift, not just a job change. First part - When to know when it is over? In the simpliest form, when the jobs availabl

It appears you are talking about a MAJOR shift, not just a job change. First part - When to know when it is over? In the simpliest form, when the jobs available suck. Either the pay or the volume. When I have changed it was both. So actually this is how you know you should have changed a year or two ago. Second part - What to do next? That is a gamble. Anything that is up and coming has a risk of being overplayed (too many others going into it) or fading out. This then becomes an issue of your objectives: 1) Write books 2) Become the industry expert 3) Just make good money 4) Be happy If you are #2 or #4 then it involves exploring a few technologies, I recommend either MOOCs or reading on forums, to decide what excites you. If you want #2, you need #4. #3 You still need to explore, but I would start with what you see job demand for. Then explore MOOCs to see if you can stand the tech. Then be sure there are enough resources available for you to learn enough to be hired. You might have to do some pro bono work for resume food. #1 - sorry no clue. What ever you choose you cannot rest. You must evolve, why? 1) others will compete and drive down the value of your skills 2) because you do not work cheap, there is a large profit motivation to make your skills more of a commodity (easier for #1)