One requirement of being able to ER was that I would not have to make any changes to my day-to-day lifestyle. I built into my budget a small cushion, or surplus, which would cover me in case I went on a little splurge once in a while. I refused to put myself into a situation where, if I spent an extra few hundred dollars in a month I would have to worry about offsetting it elsewhere or later on. All that would happen would be the cushion disappears temporarily.
Everyone budgets differently and its hard to tell what you consider day-to-day vs someone else. Most people I assume have a number for necessities, and then a rather large bucket for discretionary which was my point, cutting that isn't a big deal. Personally we use to spend $2k/month of food and alcohol for 2 people, we have now cut that back to $1k/month. If we had wanted to keep that lifestyle it would have required us to save an additional $400k .. I'm just saying we looked at the trade-off and for us, it made no sense to work longer just so we could go out and eat ridiculously fancy dinners. We certainly are not deprived at $1k/month, but we do have to say no at times to fancy dinner events.