I worked as a "sales engineer" and IT technician for 6 years, then went to law school and worked as a patent lawyer for 10 years. The patent law job requires an engineering degree (or a hard science degree), but for the most part the law job was not an obvious offshoot of my first career.
I feel fortunate to have had two six-figure careers. But to the question of whether I was more satisfied in my second career, I was not truly more satisfied. My two law jobs were more interesting, but also more stressful and more demanding of my time, than previous jobs.
Did I rely on savings in between? You bet, three years of law school were financed both from savings and low-interest loans. It is also worth noting that I did not earn a paycheck during those three years, so opportunity costs were high.
As to what motivated me, it was a layoff that got me thinking about going back to school. I was generally bored in my IT jobs, but the money had been too good to seriously consider leaving. Getting laid-off was the kick in the pants that got me to make a change.
What would I do differently? I would have looked for work as a patent agent first. You can work as a patent agent (in the US) without going to law school. You have to pass the patent bar, which requires some study and practice, but a properly motivated person can pass it. If you like the work, then you can decide whether to go to law school (either part-time while working or full-time). Patent lawyers command a salary premium over patent agents, even though agents can do a lot of the same things as a patent lawyer. A patent lawyer, since they are licensed by the state to practice law, can advise clients on things an agent cannot -- basically any legal issue that they are competent to advise on, and most obviously other IP law such as copyrights, trademarks, trade secrets, and such. As a result, a lawyer might have a more varied workload than an agent. A patent lawyer also tends to have better job security than an agent, although this is very specific to the individual. But it's not all roses and sunshine being a laywer. A patent agent generally has fewer expectations placed on them. A patent agent will be expected to bill time and perhaps train new lawyers and agents once they have some experience. But they are not allowed (by law) to take an ownership stake in a law firm and as a result, the agent will not have the same demands placed on them as far as taking a management and business development role (which is always work in addition to your billing requirements) and an agent will never get the sales pitch to buy into the firm. (The sales pitch is presented like a promotion (e.g., making partner), and so turns the decision of whether to buy into the firm into a career move decision, with lawyers usually ignoring whether it is a good investment decision. As an investment, it is far from clear that it is a good one, especially for someone with FIRE goals. But that is a post for another day.)