10 mins of Windows 10 set to metered mode (though tbf there were a few app updates because I haven't used my laptop in a while)
Got an electrician in and my power is off for like an hour, so I'm using my laptop on mobile data for a bit
So in 10 mins it used 1.33GB, but over the whole hour it used 3.1GB (of which most was YouTube videos)... It almost used more data in the first 10 mins that it did the whole hour