In reply to moderatemat: If you are soloing you may find one mat if not much use apart for near the start. For things of a more modest height try and consider where the hard moves are and in which direction you may fall. If you fall off and miss the mat you know where to move it to! Sometimes I will put the pad over a rock/boulder that could cause injury rather then where you actually land.
I have 2 mats and find carrying them OK unless it's really windy, it's great to have a spare one to pad out uneven landing zones.