As someone who started out very poor, and is now ~ 30x above that. I strongly subscribe to the idea that happiness from income is very logarithmic. The first 2-3x income was life changing. I'm talking going from eating pasta, rice and beans for most meals to fresh fruit and veg, lean cuts of meat. From renting a room in a noisy apartment with 4 other people to having my own place that was both safe and quiet. My reading list was suddenly more constrained by time instead of price or library backlog.

I suppose it's down to my starting position, a content disposition and a boring lack of imagination, but my expenses have now ~ 5x'd what they were when I was on the strugglebus, but still very modest, and I honestly can't identify any spending that would make my life better or make me happier long term.