A: Style Master says - If I had a whip (maybe I do, maybe I don't), I would crack it now. Elbow patches are best when patching a hole in a well-loved garment. If the hole appears on the left, only patch the left. Symmetry is for suckers and the quirk of one-sided patching gives a whiff of old establishment thriftiness.
Admittedly, this year, elbow patches are everywhere (AGAIN in 2012, I wrote this nearly a year ago). So, I concede to the inevitable, the same way Indiana conceded to the feisty Marion Ravenwood.
If you must buy a garment with elbow patches, make sure they COVER the elbows and not the upper arm or forearm. If they don't, someone should conk your crystal skull.
(Note: if the patches are misplaced, consider having them moved to cover the elbow.)