When you share something with someone in SharePoint, the system makes no connection to why they need it.
That makes it very difﬁcult to review whether they should continue to have access in the future.
When somebody no longer needs access to something, nothing happens. There are no prompts, no automated detection of unnecessary access or changing circumstances - their access just persists.
With so many sprawling sites, broken permissions inheritance, so many ﬁles and so much business change – it is very hard to keep control.
And so, people tend to accumulate access to information over time.
We call this, ‘Privilege Creep’.