This is my 3rd year and I started losing them on Memorial Day a year ago. Lost my 5th just this past weekend. Of the 5 crashes here is the reasons:
1. Ultra Stick 60 - Last Memorial Day doing aeleron rolls - got to close to ground inverted and pulled the stick when should have pushed.
2. Ultra Stick 60 - 2nd of same plane - Built by someone else (just transferred the radio, servos and engine to it) Coming out of a Split "ess", the right wing broke at the wing center, rest of the plane was a lawn dart. I found out that when the wing was assembled, very little epoxy got on the front of the right wing joiner block. Could have happened to anyone.
3. Funtana - Dumb thumbs - aeleron rolls on high rates, came out inverted, and did do the right thing, pushed up on the stick started to recover and accidentally moved my thumb a little to the right engaging the right aeleron, spun it right into the ground.
4. Avistar Trainer - (My original plane) Hit a bird head on during a boy scouts day at our field. It was the 11th flight that day.
5. Magic Extra - Last Sunday - Took it to the field and tried flying it in a crosswind. The heaviest that I have ever flown in. Took off, flew great, and missed my first landing approach. On the abort, I turned to the right to go around and as soon as the wing was 90* to the wind, it pushed it right into the ground.

So you see, it can happen anytime, and for any reason, the goal is to reduce the possibility as much as you can. I am now getting a low wing plane that acts more like a trainer and going back to basic practice, especially the crosswind situation. I will still practice aerobatics and manuevers, but need to get back to basics on my flying as well. I certainly won't mind the practice.