Chesterton's Fence
The principle is simple, “Do not remove a fence until you know why it was put up in the first place.”
Fences do not grow freely from the ground or are a byproduct of another process. They require planning, effort, and resources. It is far easier for there to be no fence than for one to exist, so it follows that before you decide to take it down, understand why someone went through the effort to erect it in the first place. It is an exercise in systems thinking and second order consequences.
What if that fence was built to keep something bad out?
There is a trap and condition where we think that the work that has been done by those before us was poorly done and not well thought out. I have found that this line of thinking is usually the exception. That does not mean that prior decisions that were made were necessarily the right ones, but rather that they were made with a degree of thoughtfulness and care. It is important to understand the reasons that led a team to the current path before you endeavor onto a new one.