I recently quit my job, so I'll be living off my savings for the next couple years, as I try to build up a lifestyle company (and hopefully eventually live off recurring revenue from this). Keeping my personal expenses low is exactly what can let me stretch this runway enough to make my professional goals a reality. And as we all know it's much easier to optimize something when you measure it. I'm not sure totally exact accounting is needed, but keeping track of recurring expenses and budgeting in general seems essential to make this work - it'll let me know if I actually have 2 or 4 years of runway, force me to consciously make the choice "is this expense worth what it does to my runway?"

That said, hopefully after the schlep I can go back to the state you describe, plus have much more freedom in how I spend my time than if I was working a full time job.