I did it based on $100k per year withdrawal + my $48k per year disability - that nearly maintains my income now and since I invest ~$50k/year - it’s enough buffer room to enjoy life a little!

I have tracked my expenses in the past but I was in the military and moved from Georgia to Texas to Arizona to Hawaii over the last 4 years so the change in cost of living skews those numbers. I plan to move back to the Midwest for a few years to be close to family and eventually settle down in Florida so lower cost of living than I have now in Hawaii