I've thought about it and realized if I were retired, I probably would spend less. I estimated once I spend about $210 a month on being employed in clothes I wouldn't otherwise buy, travel expenses otherwise not incurred, buying conveniences like pre-packaged granola bars which I would just make myself if I had more time, money I spend on the occasional lunch or gift that is work related, etc. None of these amounts is terribly large on its own but there's a lot of them and they add up.
That's not even considering that I live in a higher COL area to be able to find the work that pays me the best, so if I were FI I could live somewhere much less expensive.
I think everyone should try to have an FI plan even if it's not a rosy, 10 years and you're idle the rest of your life plan. In other words, I think you should "Rush" to FI as best you can even if you're not "rushing" to not work any more.
I used to work with several retired gentlemen who just got some low paid job related to a hobby they enjoyed, like a man I used to work with who liked wood working so he worked in the tool department of a home improvement center; he got to talk to people about tools and projects all day, which he enjoyed, and he got a discount on tools and materials for his spare time. Oh, and the money he made paid for the hobby so he didn't have to touch his nest egg.
He probably could have even made a little money at it, but he tended to make pieces for free and would do stuff like make bunk beds for children in state facilities, or build wheelchair ramps for seniors on a fixed income, etc. He got to smugly refuse any compensation for it too.
The thing is, when he retired, he didn't plan on this. He just kind of figured it out after a while because his new "job" was to amuse himself and do things that were important to him even if he didn't know what that was initially. If he wasn't FI he couldn't do that.