Opening the book…
Money without a job tends to wander off. Cash sitting loosely in a checking account does not announce its purpose, so it gets spent on whatever is nearest. Giving every dollar an assignment, this much to rent, this much to saving, this much to genuinely spend, means the deciding happens once, calmly, in advance, instead of a hundred times at the point of sale. A budget is not a cage. It is a plan you made when you were thinking clearly, so your tired future self does not have to.
Start from your take-home pay and assign all of it, down to zero, before the month begins: bills, savings, giving, and a real category for fun. The fun line matters, because a budget with no room for enjoyment gets abandoned by the second week. Keep the categories few and broad enough to remember. When something unexpected arrives, do not tear up the plan. Move money from one job to another and note the trade. The goal is intention, not perfection.
Irregular income makes strict monthly budgets hard. If your pay swings, budget from a buffer of last month's income rather than this month's guesses, and assign jobs to money you already have. The method bends, but the habit of assigning stays.