Everything in real estate has to be in writing. The statute of frauds refers to the requirement that certain types of contracts be in writing.
With so many back and forth negotiations, numerous email and text exchanges, and the most dangerous... phone calls (that don't leave an organic paper trail), putting every detail on paper is essential.
While everything must be in writing, I think we also must honor our word.
At the end of the day, be a good person. If you agree to do something, do it. If you agree to make a repair, make it. If you agree to leave behind a piece of furniture, leave it.
Even if the change was not documented. Even if the change was documented, but not initialed.
Even if the changes was documented, initialed, but not dated.
Don't be the person that forces more rules to be made for the decent people in the world.