My "splurges": I give myself $150 a month to go out to eat. $30 to treat myself to a nice coffee every once in a while. $100 on video games. That going out to eat and coffee budget is part of a $200 misc budget (so I could decide to do a show instead of going out for example). I stick to my budget... but I am not leaving myself a ton of money here. If I got all of that, that's $300. But then... why bother working if I am just going to hate my life because I literally can't do anything?
That $300 is not going to make the difference between this being sustainable and not.
The small stuff is not the problem here.
Edit:
Regarding your yearly big stuff, I agree and that is taken into account as well. A couple years ago I put in the hard work to figure this out and I have continued to adjust it as need be. It finally hit a point this year that my rent raised higher than my pay raise (plus everything else going up) that I had to make the decision to cut things like Netflix. It is at the point that I feel like I have made nearly any reasonable cut I can make without removing my ability to at least do some things.