I feel that the way security works in SharePoint, breaking role inheritance and adding unique permission to item can complicate the things if your list grows and have thousands of items. As the permission scope will be calculated for each permission assigned to that item. Hence if let us say 1 item has 5 unique permission, and you have 11,000 items in your list down the line, you will end up having 55000 permission scope / set.
I was not sure if something we can do to avoid these situation and still use the item level permission or is there any guide that talks about nintex workflow - permissions best practices.
Thanks,