When people do a project one of the most frustrating things to hear is “can we get just one more thing”.
First of all, when you keep asking for “one more thing” the reality is it’s many more things.
Secondly, that one thing might have been simple to do if planned in advance but when added on later might cause huge conflicts with things that have already been done.
When planning a project, finalize your plans ahead of time with the assumption that no “one more things” will be added later. If you do this properly, they wont need to be added later.
Have a great day!