I've gotten myself confused. My thinking was to use my 4x4 when I thought I needed better traction (wet roads where I feel myself start to slip, sand, mud, etc).

Reading up on it however has me baffled. "Use it in wet pavement" "Don't use it on pavement at all!" "It puts too much stress on the components".

Is it worth it? When should I use it?

 

I believe that you have 2 4x4 options: 4H and 4L . Do not use either on wet pavement, as it is not slippery enough (usually) to allow your wheels to turn at different RPM's as it would when locked up in 4wd. The easiest way to tell if the surface is ok to use 4wd is to put it in 4, then drive in a tight circle. If you feel binding or hear clunking, then it is not a good surface to use it on. The binding is caused by the tires rotating at different RPM's ie: outside tire in a turn goes faster than the inside tire/ front tires move faster than rears in a turn, pivoting about the rear axle (since the rear tires dont turn). As all of these components are linked together in 4wd, the surface must be slippery enough to allow the front tires to move at the same speed as the rears, despite the turning arc being different (in other words, they have to be able to slip). As far as the link betwen left and right tires on any given axle, that is why we have differentials (limited slip and "open") to allow tires to move at different speeds. The 4wd transfer case does not have a "differential" that is sufficient enough to compensate for the differences in tire speed, thus putting binding pressure on driveling components.

4H vs 4L is just a gear reduction option: 4H is for going the same speeds as in 2wd, 4L gears the truck down for low speeds

 

I am VP of an offroad club and have been building offroad rigs for years. Everything quoted here is perfectly accurate. Hit the nail on the head