When I was in college, I never had a budget. I didn’t keep a budget because most of my expenses were paid for in a lump sum at the beginning of the year. My room and board were all integrated into that payment, which made for a pretty simple financial life. The extent of my purchases were at the local bar or at the grocery store when I wanted something a little more interesting than what was available in the fraternity kitchen. I had little income, little expenses, and almost no need for a budget.
That all changed when I started working. Here I was, with a real salary, real expenses, and little by way of advice on how I was supposed to track anything. Fortunately my friend sent along an Excel spreadsheet she used to and that got me on my way. I quickly learned I was spending way too much on food, specifically a mediocre lunch in the cafeteria, and was able to adjust my spending to reflect what I wanted. I learned that having a budget is absolutely crucial.