[kumarvvr]

You change the position of the tires. The front ones are removed and fixed at the rear and the rear ones are removed and fixed at the front.

Allows for uniform wear and tear for the tires.

Some even interchange the left and right tires.

[skoocda]

Left <-> right interchange doesn't really happen anymore since radial tires have become standard on most vehicles.

Radial tires are unidirectional, so if you go left -> right your tires will be rotating backwards, and then they won't be able to channel water out from the treads.