The first time I transitioned to a different type of job in tech was really tough but I had been pretty unhappy for a while. I wasn't pushed out--the opposite in fact--which made leaving tougher but subsequent events showed it was absolutely the right decision. The next time, my hand was pretty much forced by any clear-headed view of company financials which made it a lot easier to get on a very interesting (and better compensated) track through someone I had done some work for. At the end I wasn't especially happy but it was around the time I was planning to at least semi-retire anyway so the decision was straightforward again.