Long-term financial planning is a very important thing, but things are always changing—the world around us is changing, and our personal goals and pursuits are also changing. Saying "I don't know what the future holds" is one thing; admitting that the present self doesn't know what the future self wants is another. In fact, very few people can know what their future self will be like. If your future thoughts may change, then it's difficult for you to make long-term decisions and stick to them.