10mi of 4x4 per month - According to Manual

I engage mine 2-3 times a week on a short gravel .2 mile road, so it keeps the gears lubed. The more often it gets used, the quicker it clicks into 4hi. I tested 4lo to make sure it works too, no problems there. If nothing else, I'll drive all over the yard to give 4wd a little workout, lol.

 

wish i could but my yard is the same length as my truck

 

I live it the city and also take my truck to the cottage.... I do drive my truck in 4W-HI and 4W-LO once a week just to keep things turning proper... driving on dry pavement in LO or HI is fine as long as you're not turning the wheels...which if you tried it you will know right away that ain't good.
Going straight wont hurt... the clunking into and out of gear happens to me if I don't do the 4wd thing weekly... best to use it even if its in a straight line.