I ER'd 5.5 years ago. I noticed pretty soon that my spending was below what I expected it to be. The decrease was entirely voluntary. The decrease wasn't just associated with lower w*rk related or commuting expenses. It is just that a lot of my previous spending became unimportant to me once I ER'd. Lately I've chosen to start spending that "windfall" on travel.
Of course everyone has individual circumstances to consider but this pattern of retirement spending seems reasonable to me. Or . . . it seems to apply in my case.
Happy, Wild, and Free