[jamal]

A tire that is leaned over will want to move that direction due to what is called camber thrust. Slight toe out on a wheel with negative camber will counteract that and make the tire want to roll "straight" and reduce wear. The number I see in books is about 0.1 degrees of toe for every degree of camber.

However, there are other things going on, like deflection of suspension components/bushings/wheel bearings etc when the car is rolling. The drag from the front tires is generally going to push the toe out a bit, so what is set statically and what occurs when you are actually driving are two different things (conversely, the driven rear wheels are going to want to toe inward).

Plus of course the changes due to suspension travel. While bump steer is fairly minimal it is not exactly zero.

So yeah, in theory a little toe out should help wear especially with a good amount of camber. in reality setting toe to zero or slightly in tends to be more popular.