I reuse them if there is no damage. I have changed maybe 10 wheels/tires and found the o-rings fine for reuse except for 2 that had not stayed in the groove and got smashed. That damage is obvious (but they still held air). BTW I use regular grease on the o-rings and they 'squirm' right into place when the wheel halves are tightened.
Ok Wes, you can get off the floor where you are rolling in laughter at my declaration of having done 10 wheels. You would do that many in an afternoon
Be sure you check your valve stem seat too. I just tok one apart for the second time to fix a loose stem nut...mutter mutter.