I spend much more freely when I make a lot more (I’m a contractor), however I do aim to keep my fixed expenses very similar to if I was FIRE’d or unemployed.
5 years ago when I was making around $130k/yr, I was spending about $5k/mo on a good month.
The last couple years I’ve made around $300k-$320k, and this year will be closer to $350k. Right now, I can survive just fine off around $6000-$6500.
Of course, right now at my income I do spend way more. Not on items that add higher fixed payments, but more on discretionary stuff. We have a couple newer cars. We don’t hesitate buying top of the line items that should “last forever.” I.e. a Vitamix blender, luggage with a lifetime warranty, nice tools, home gym equipment, travel, nicer clothes, etc. I’m buying things now that should last well into FIRE. The expensive things I want to buy aren’t conducive to the amount I move for work i.e. items I don’t want to move a lot (high end stereo, guitar/amp, high end welding machine). Those will be purchased whenever we someday buy a home.
I do keep myself in a position where if my income was even cut and half, I could still save 50% of that amount if I wanted to.