In my M4 I'd have DSC on about 50% of the time. For local driving or places without much traffic I'd go MDM. If I was out in the countryside and knew I could recover without risk of other cars/people I'd usually turn the bells and whistles fully off.
However, in my GT3 I leave it on about 99% of the time. I've experimented with it off and once the back starts to spin in that car, it's basically already too late. I've also done driver control training on a track with full instructor, and understand that my recovery in the GT3 with DSC off simply isn't as controlled as it was in the M. I don't want to risk that on any public roads...and also I'm just a helluva lot more careful in that car in general