Mistake _ Not Planning for Upcoming Expenses _ When you are creating a monthly budget it is always helpful to save a certain amount of money for a given category even if you don't have that expense for the given month. For example, let's say you pay your car insurance every six month. It is important to take your payment and divide it by six. Then, each month you will want to save that amount so you have the insurance payment when it comes due instead of trying to come up with the whole amount in one given month. If you can do this for as many periodic expenses as possible, it will be easier to have a balanced budget each month.
When most people hear about creating a monthly budget they run the other way in fear. They just don't know where to start. It certainly wasn't something that most of us where taught in school. However, it would have been more useful than some history lessons.