Save up a bunch of money with your high paying dentistry job, then retire once you have anywhere from $300,000 to $1,000,000 in the bank (divide your savings by 30, and that's how much you get to live on per year for the rest of your life) and live a low-cost lifestyle like INTPs/INTJs generally do not mind doing. Then you can spend your time doing What Really Matters to You.
That's my plan, except I'm going for a bookkeeping service to make my money.
This is feasible with certain lifestyles, and in certain locations.
For example, I dream of having a residence far away from people. I want to be self-sufficient, and limit my contact with the world.
Now, with $1,000,000 in the bank, I could do that... If I wanted to move to a country or a state with very low property tax. I could buy land that isn't worth much, and fix it up to my liking and hope that the "gummit" doesn't notice the value increase. I could then retire, put my money in an account that made enough interest to pay my property tax each year, and then live off the land.
Of course, if I needed any money for anything, I'd be in trouble. Not at first, of course, but eventually. For every bit of the $1,000,000 I spend, the interest it creates decreases. As the interest decreases, and property tax increases, I'd have to spend more and more of it to cover the property tax.
As I slowly creep up in age, my distance from civilization will no doubt frighten me. I'll have increased need for medical attention, and aid in my daily chores. I'd have to sell my bit of land, and actively live off what little (with inflation) I have left. There's a good chance I'll run out before I die, and without any children to care for me in my tottering old age, I'll probably pass in a sub-par nursing home with $30/month allowance after the home as taken my whole SSI/SSDI check (if that kind of thing even exists when I reach that age).
Theory is all well and good, and I'm sure most plans will feel wonderful for most people until they're about 60. If all else fails, you can get a job, rough it a bit, whatever. At some point though, your energy will run out, your motivation to scrape by will be gone, and you'll wish you had put in a little more work when you were able-bodied.
At least that's the biggest regret I see among our aging homeless population.
