The main factor is time. It’s almost like countdown device
My experience on the 3.7L is that it doesn’t like inactivity. It actually seems to reward you for a few days after a long trip.
I never tried to pull a trailer at high rpms in mountainous terrain, but more heavy duty use didn’t seem to make much difference.
When you think about it, that’s probably about right. Modern oils eat it up and spit it out assuming reasonable change intervals. The “Everyone is a severe service driver” thing is a myth.
That said, the IOLM on my Ford had almost zero margin of error when I tested. When I ran it all the way down, almost 9,200 mi. it was OK—-but only a few hundred miles from failure.
If I were relying on an IOLM for an Ecoboost I would change at the 25% 30% oil life remaining mark