When a device has wifi enabled, it sends out a wifi probe request, containing your signal strength, SSID, and MAC adress. I was wondering, how often does a device send out this request?
I heard that when a device is connected to wifi, it will double the time each time that it sends out this request.
I recommend this paper. It says that a device may do a probe request anywhere from 55 to 2000 times per hour.
On smartphones in my home network, I measured an interval of about 7 - 8 minutes when the phone is left untouched, but much shorter (a few seconds) if you're actually operating it.