I have a client that has over 50 subsites of the root site in a SharePoint site collection that are all pretty much the same. There’s a site for each county in the client’s state, each one with web parts to show some data from the root site that’s relevant to that specific county (contacts’ information, documents, that kind of thing). Whenever they wanted to make a change to, say, the contacts web part for these county site, they had to modify over fifty copies of the same web part. Tedious to say the least. After a few rounds of making these kind of repetitious modifications it was decided that I would need to come up with a solution to make managing this stuff much easier.
So I did.
In this way I was able to remove the headache of having to modify 50+ web parts across 50+ sites and instead only have to apply changes to one central location for it be reflected across all the subsites.