It's worse than that, it assumes that where you want to be in 5 years won't change during that time. My experience is that our needs and wants change over time

It's worse than that, it assumes that where you want to be in 5 years won't change during that time. My experience is that our needs and wants change over time, and they are shaped by our actions. Overcommiting to a future that we think we want can end up quite badly in my experience.