Like others I have this laptop and since the DELL approved upgrade to Windows 10 - WIFI drops out after usage that can only really be solved by a reboot. I have done some experimentation and it seems to be unrelated to the drivers and card you use.
I get the issue with the onboard N230 card (with either 8.1 or 10 drivers from Intel). I also get the issue if you disable that card and use a Netgear micro USB wifi card.
So the issue seems to be not related to the hardware or drivers - but some sleep setting or other factor with the 7520 as the IP connection continues to work - can still print over the connection etc, and ping all local machines and hubs, just can't browse the internet...
I have seen the posts from a number of guys with this wifi drop out issue issue and wondered if DELL or anyone had got to the bottom of it yet?
At this rate I will need to either re-install Win 7 as I am post the 30 days - or get an HP laptop....