Property tax is my largest projected "mandatory" retirement expense at present. It's followed by property-related expenses (gas/electric, water/sewer, insurance, garbage all in this category), then finally food. There are a few other inexpensive mandatory items..soap...toilet paper, clothing once in a while, although I have enough clothing to last a long long time I suspect.
Everything else gets lumped more or less into stuff I like, but could do without if it came down to it. Being able to cover that mandatory set of items to me is where I reach FI. I am unlikely to retire at that point as I want money to do stuff I like, but once those items are covered that is the point at which I will really have FU money where I could walk out and not worry about how long it takes to get another job. I have quite the backlog of things I could entertain myself with for little additional outlay as well since currently the problem is more about time to do things than money to do things. There are a ton of hikes locally that I would like to do. I also have a giant backlog of video games I would like to play someday that I already own in my Steam account which I acquired cheaply. However, there are also many things that will require some money which I want to do: visiting the rest of the states I haven't seen yet (~50%). Visiting other countries is also an expense on my future list as I have not been outside North America. I may consider working in a foreign country at some point in the future and using that country as a base to visit other nearby countries while still having an income.