Some people will dismount the right rear tire from the rim, and remount it on the opposite side every 10k miles. Some people do it more often. If you can notice any uneven wear with the naked eye, then that would be a good time to swap sides.
Since most all the 19" tires I've seen are uni-directional, doing so will automatically put the tread (that's wearing down faster) on the outside of the tire, and the tire will then have the deeper tread on the inside of the rim. Thus giving the tire a chance to wear more evenly.
It will extend your tire life.