How do you tell a right or left hand sliding patio door?

There's a "butt to butt" method that I SHOULD remember, considering I sold doors for six years... But there's an even easier method: Go to whichever side of the door you can see the hinges on--if the door's inswing like most of them are, that's inside of your house. If the hinges are on the left side it's a left-hand door; if they're on the right side it's a right-hand door. From the other side of the door, go by where the knob is. The easiest method to identify door swing is to simply pretend you are the hinge. It doesn't matter if the door opens in or out, or if the hinges are on the right or left. One side of the hinge is attached to the door (and swings with the door). The other side of the hinge is attached to the door jamb and does not swing. Simply put your hands together in front of you and swing the hand that would be attached to the door. If you swing your right, it's an RH door - if you swing your left, it's a LH door.