1. I am trying to determine the difference between emergency fund and FU money. I seem to be reading different personal definitions. How would YOU define them?
Our emergency fund basically covers our medical and car insurance deductibles in case of a major accident. We don't own a house, but if we did, I'd want more in the emergency fund in case a pipe burst, etc. I'd agree that FU money is an additional stash that would allow you to quit your job and not worry about finding a new one for at least a few months (for me, I could be looking at a 6-12 month job search, but in other industries, that could be much shorter).
2. How would you calculate FU Money?
I'd want enough to cover our "essentials" (rent, utilities, food, health ins.), plus some extra to help with a nationwide job search (I've traveled to Chicago and Florida for interviews, and these costs can rack up quickly).
3. Where would you keep your FU Money so it's still working for you?
We kind of have an FU fund that's in stock that we could immediately sell, if needed. It's a taxable investment account through Fidelity, which is also where we have our checking (brokerage) account so it could easily start paying for our rent and food as soon as we sold the stock.
I'd also add that I think FU money is different than FI money, at least for people who aren't into early retirement. For example, I've talked to one of my family members who makes good money about early retirement. He likes his job and the money that comes with it, but I suggested that he could max out his 401k and not even miss the funds, he was skeptical. But when I said, "well, think about it like this... if you saved more money, you could say 'screw it' when things got stupid at your job and take off 3 months to go skiing in the mountains, and then get a job whenever it suits you" and he seemed to like that idea more than "early retirement." It's really just a terminology thing, but getting people to put aside a year's worth of living expenses probably seems a lot more do-able to most people than saving for "retirement" which in most people's minds is a lengthy period of time in which they are old, maybe sick, etc.