110 is used for -
Carrying stuff on road (up to half a tonne fairly often, somtimes more)
Towing
Some motorway driving (without much weight)
This is the common stuff.
Also, but less frequently -
Snow / flooding (happens every couple of years)
Mud (just general fields, hills, nothing cross axeled)
I don't do any serious off-road, but might if I had the kit - and if im buying kit, i may as well consider this.
The main reason for the diff stuff is simple mud (and snow which I hear mixed reports on the Detroits, but no one specifies which one). But I need to maintain the ability to drive down the motorway... I do very very little town driving though.
So it's motorway miles or work.