I would probably not say frequently, but it's one of those things that would seem to popup due to errors, omissions, changes, etc. When you need to adjust the structure, to not be able to at all would be killer, IMHO. Depending on one's scenario, I would think having to create that perfect structure the first time, every time, for all time could be a bit challenging. Once there's a ton of images involved, recreating for a structure adjustment would be a daunting task.
Regards,
...Bill