Slightly off topic: what prompted you to leave nephrology? That's not something someone would do lightly, to say the least.
Previous thread on it.
In summary, my side business (macrumors.com) became successful enough that it made significantly more than my income as a doctor. Combine that with the lifestyle of being a doctor being bad, and wanting to spend more time with my young kids. It was still a hard decision at the time due to the sunk costs of becoming a doctor but on paper it was an easy decision.