Coast FIRE is the liberating one: instead of racing to a full retirement number, you save hard early, then coast — your existing pot grows on its own to cover retirement, and you only need to earn enough to pay today's bills. The catch is knowing the exact point you've hit "coast", because before it you're still on the hook, and after it you've bought yourself a lot of freedom.
That's what this works out: put in your age, what you've already invested and when you want to retire, and it shows whether your current savings, left alone to compound, would get you there without adding another dollar. Try it — and if you're not quite at coast yet, nudge the numbers to see how much more you'd need to stop the heavy saving. It's often less than people expect (compounding does the boring, brilliant work in the background).