A lot of times, there are entire teams working on sites who all have the same permission authorization. If this is the case in your company, then you can simply assign the same permissions to all of the employees with one action, instead of doing so for everybody separately. It is important to note that in order to create such group sharing permissions, you will need to have the “Full Control” level yourself or another permission setting that lets you manage groups. While this is one of the SharePoint best practices, it is recommended that you retain all of the default SharePoint groups. Otherwise, if you start deleting them, the system can become unstable. As a general rule, you should only delete the groups that you will definitely not be using.