Hi Bill....welcome to the Club
I have always been of the belief that it is not advisable to drive in 4WD High or Low on hard road surfaces, as this can lead to transmission wind-up which can damage internal components.
You will notice a clunking on cornering at slow speeds which is the transmission (differentials) fighting to corner at different speeds.
If you have freewheeling hubs disconnecting the drive to the front wheels then this helps but not good to use on the freeway, best for off-road driving really.
Saying that, it is necessary to drive on soft ground in 4WD every so often to keep everything moving otherwise this can lead to components seizing in position (selector levers, etc)
I drive my Mitsubishi L200 in 2WD and occasionally shift to 4WD High and into 4WD Low on dirt tracks