There are many reasons for why we do not change. Some of the excuses are identified here.
Think about this. If you really want to change, are these reasons not to?
We may feel these are "safeguards" which protect us, or we might assume these to be "cast in iron" requirements or procedures. But often when they are investigated, they are found to be movable, and thus "changeable."
We simply need to recognize that they are really only an "excuse" not to change.