I started budgeting while in college. Having a budget is easy. Staying within that budget is always harder...
Another problem with budgets is... they have to have good priorities. While I religiously paid off my credit card bills after college, my budget always had an allowance for car payments--but none for retirement. Later on I had no idea how to make it balance: if I penciled in some amount for house repairs, and car repairs, and then all of what life costs on a regular basis, it was always red. Took a long time for the drawbacks of car payments to really set in. My wakeup call didn't hit until I was 36. By then I had bought the wrong house (I might have carefully shopped and kept it to 2.5x my salary, but sold later it for a six figure loss), got married and had kids. Couldn't undo any of that.
So I've spent the last 7 years attempting to fix that. 15% or more to my 401k (although covid reduced this, no company match), max out my HSA contribution, no debt other than a mortgage. Wife says we have 5 months of net income in savings, and my HSA has 2 years max out of pocket in it. But. I still screwed up: two kids with zero college savings, and they go in less than 5 years. 29 years left on my mortgage. Still not regularly putting money into my savings account (only bonus money goes there it seems)--I am still living paycheck to paycheck.
I'm living above my means, I'm afraid, and that's with a budget. Ergo, no nice cars for me, and whatever I have, has to be cheap. And long lived. [That is why I keep wanting to get rid of my truck--I like it, but it's really just a sign of living outside of my needs. But darned if the temptation keeps hitting every year to get something "nicer" or newer or whatever--that is why I keep participating in these discussions, to keep myself rooted in reality.]