Well I have a Lumia 650 that I bought in March 2016 and this did have the problem that it would sometimes not connect to my local WiFi and needed to be switched off and on again to make it connect again.
However I have not had the problem for a few weeks now despite regularly switching on and of the WiFi and changed to the Bluetooth connection when I am travelling in my car. I have not changed the WiFi or Bluetooth settings.
Perhaps Microsoft have fixed this in one of the OS updates they have installed recently or perhaps they have upgraded the firmware.
I would be interested in a comment from Microsoft but in my case it now seems to be fixed.
Regards
Gordon Webb