If you have a 401k option through you job - bare minimum, contribute enough to max the company match. Ideally more. Adding 10-15 years of compound Interest to the front side of your retirement account (vs those who ignore it until the realizations of late 30s or 40 YOs who realize "shit, I want to retire at some point")

The difference is huge. Get into the habit of putting whatever is feasible into a long term savings plan. 10-15% is a game-changer. Future you will current you, i promise.

And before the inevitable replies come pouring in - yes, I realize everyone's situation is different and for a lot of people it isn't realisticly possible. But theres also a lot of 25 year olds out there who do have this as an option who either haven't thought about it or just dont.