> I don't understand why someone would FIRE and not already have spent years lining up all the things they will do.

It's a common phenomenon in those communities because many of the participants are young (the E is for Early retirement).

The common way to get to FIRE, unless hitting the lottery or getting a crazy RSU payout, is to be super frugal with a high savings rate.

Then they get to retirement and realize that doing the amazing things like traveling the world requires a lot of money. Even many hobbies start to require money. Then reading books, browsing the internet, and playing games starts to get boring when it's your entire life.

The people that make it work usually take RE to mean “recreationally employed”. They aren’t sitting on a beach. They have a challenging project they are personally obsessed with that also generates income, but the income is largely just a way to keep score for them.

> The common way to get to FIRE, unless hitting the lottery or getting a crazy RSU payout, is to be super frugal with a high savings rate.

Then they get to retirement and realize that doing the amazing things like traveling the world requires a lot of money.

Partition living expenses from hobby expenses, and once you have enough to not have to work for living expenses switch to doing just enough part-time to cover hobby expenses?

> Even many hobbies start to require money.

Hobbies require money, but a lot of hobbies don't require very much of it.

Yeah, if your primary hobbies are skiing and golfing and traveling and rebuilding 60s cars, that's not going to come cheap. But there is no shortage of much cheaper hobbies.