WiFi is a precious resource, and you don’t want other people—house guests, neighbors, relatives, delivery drivers, hackers sitting at the end of your garden—accessing it without your permission. With that in mind, it’s a good idea to regularly audit who’s accessing your WiFi and kick off any unwelcome interlopers.
https://gizmodo.com/how-to-make-sure-no-one-is-stealing-your-home-wifi-1851468625