One piece of the puzzle isn’t fitting with the rest of them.
Putting a budget together is kind of like trying to assemble a jigsaw puzzle on a massage chair. You’ve got all the pieces and have a rough idea of where they’re supposed to go, but the world around the puzzle keeps shimmying and shaking all over the place and making it hard to keep things straight. Of course, the world isn’t the only thing making the puzzle harder; it might also be harder because of you if, say, you were trying to assemble it with a pair of tongs or something.
Clumsy metaphors aside, while there are no shortage of external factors that can thoroughly mess up your budget, at least half of the responsibility of the matter falls squarely on your shoulders. After all, a big part of what makes a budget actually work is the assumption that you’re going to stick to it long-term.
Successfully assembling a budget has a way of making you feel invincible. “I put a budget together! I’ve got money set aside! I can buy whatever I want and not worry about it!” While having a budget does help to ensure you’re able to pay your bills and keep food on the table, that sense of invincibility can be dangerous. If you start impulse spending without sparing a thought to the budget and your finances, you’ve got a good chance of going over-budget and completely ruining the whole system.
That same invincible feeling can also lead to lifestyle creep, which is when you start buying progressively nicer things for yourself whenever your regular income increases. You may not realize, but a lot of budgets have precarious balancing acts hidden within them. If you replace something in your budget with some more expensive, the system can fall apart. You can’t shove a non-fitting piece into a random spot in the puzzle.