What are the variations of FIRE?
FIRE (Financial Independence Retire Early) in the most traditional sense is when an individual can maintain their existing (or desired) lifestyle using the 4% rule. But there are actually many variations that the FIRE community has come up with over time. Here are a few of the most common ones.
Barista FIRE (where you still need to work, but in a less stressful environment, indefinitely)
The name originated from the misconception that being a barista making coffee for people is an easy and enjoyable part-time job. Having personally worked at Starbucks before, I understand how not true that is, but I digress. In Barista FIRE, your income will come from a combination of your portfolio (using the 4% rule), and a part-time low-stress job (such as being a barista). For this to work, you should have the majority of your income coming from your portfolio. Otherwise, it wouldn't really be FIRE, it would just be working at a low-paying job that doesn't pay enough, and using your savings to cover the rest.
Coast FIRE (where you can coast at work until your portfolio grows to be enough)
The magical thing about a portfolio is that it will grow over time. This is where Coast FIRE comes in and can work for those who are young and have time on their side. With the power of compounding, since the S&P500 has an average return of 7.5% per year (historically speaking), which is the foundation of the 4% rule in FIRE, we can assume that your portfolio should eventually grow to the desired amount. How long that period is will largely depend on how much you have already saved and invested, and how the market performs during those years. Coast FIRE is when this period is short enough to allow you to feel financially secure so that you feel safe to casually coast (doing the minimal work that is expected of you) at your current job while waiting for your portfolio to grow on its own.
Lean FIRE (where you have just enough to cover the most basic expenses)
Going back to a more traditional form of FIRE where you actually do not have to work another day if you don't want to; lean FIRE. A typical FIRE number would be based on an annual expense that could support a relatively comfortable lifestyle, which means there is room to negotiate to the downside. For example, you can reduce your monthly allowance (fun money), dine-out budget, travel budget, etc. By doing so you can FIRE early, but with a lean lifestyle. Not only will you limit the options you have post-FIRE (such as activities, spending etc.), but it is also rather risky that when shit hits the fan, there will not be much breathing room, which greatly increases the likely hood that you might need to pick up some side hustles one day.
Way over there: Fat FIRE
Fat FIRE is when you have a portfolio that can support a 4% withdrawal of more than your desired FIRE annual expense. This is the holy grail of retirement because the risk of running out of money before death is virtually zero, depending on how fat your portfolio is. This can happen if you win the lottery, encounter a large windfall (such as inheritance, lawsuit settlement etc.), or if a large chunk of your annual expenses disappears (such as finished paying off a large loan). If you hit this level of FIRE, congratulations! The world is your oyster.
Summary of some of the FIRE
As you can see, FIRE isn't a one-and-done concept, but rather a fluid one that can be customized to your desired lifestyle. At the end of the day, what's most important is to identify the lifestyle you want, and work towards that. Some people want to pursue personal projects, and some might want to work as a librarian or other low-stress low-paying jobs. What's your ideal lifestyle look like?