The extreme savings/retire early website/guy (can’t remember the name and googling is failing me) essentially uses this for working out how early you can retire

The extreme savings/retire early website/guy (can’t remember the name and googling is failing me) essentially uses this for working out how early you can retire by focussing on the percentage of your take home that can be saved/invested rather than out right figures. It’s the thing we (my wife and I) focus on, the percentage left over as discretionary money to be saved, invested or spent as we see fit that matters the most to us.