Yeah, figuring out what you need and what you can live without can make decisions very empowering.

The other poster mentioned the FIRE chart by MMM, so I'll take another angle on it. This site shows areas by cost of living. If you know how to estimate income generation from investments (~3% is a good rule of thumb before retirement age, 4% thereafter), you can find a place you can retire to if you have a few hundred thousand dollars/euros. If you're fine with a BR apartment, there are options as low as $600/month ($180-240k investments).

What I mentioned is called "Batista FI", so called because some parttime barista jobs provide medical benefits for even part-time work in the US. The idea is you save enough that you can live comfortably on part-time income and still meet your longer term retirement goals.

My point is the lower your expectations are for retirement, the earlier you can get there. And knowing you can retire can make working more pleasant because it's a choice instead of a necessity.