I like WiFi Guard, but the pop-up every 60 minutes is mildly annoying when there is nothing new to report. I would like to have the option to have it appear only when there is something new. Then the pop-up repeats after that. Please consider this improvement. Thanks.
The notification keeps popping up because you take no action, and thus the found devices remain unknown. Until you tell it, WiFi Guard has no way of knowing whether you recognise the discovered devices.
So, to stop the notification from showing up unnecessarily, you should simply mark the discovered devices as known. Double-click each unknown (red) device and mark it as known if you recognise it and know that it is legitimate. After that, the notification window will no longer pop up until something new is found.