When you closely follow the FIRE movement, you stumble upon the penny-pinchers. The FIRE world is full of people denying themselves five-dollar pleasures. Sure, hundreds of those add up, but is it worth burning all that energy? The major things that can financially kill us are real estate and cars (in the US, it's also education, but in the EU, that's not the case).
So those two are the things to figure out and be intentional about.
Everybody needs a roof over their head, and it's a choice to rent or buy. Real estate is always too expensive — that's the case when you're 18 and when your 48. We can decide at 18 to get into a big debt and be free at 48, never to pay rent again. Or we can rent forever and invest more to feed off of that.
We can figure out house-flipping to hack our way to the first homeownership. I wish I'd known that when I was young. When you get your first job, it's easy to live with roommates, and if you own the place, they basically help you paying off your loan.
Instead, I went the wrong way — it was easier to get a car loan and drive myself around in a pile of debt while paying the rent. That's a common mistake. Figure those two out early, and you're set for life.
A €20K car is five thousand coffees. A small studio apartment is five cars or twenty-five thousand coffees.
So don't save on coffees — save on transportation instead. Take the bus for 3-5 years, or as long as you'd be paying off that car leasing, and save that money for a downpayment for your first flat.
Figure out the big things, and the small things will work themselves out.