I voted "on first solo flight" because I was self-taught with a GWS cub, and flew directly into a stop sign 5 seconds after hand-launch. Then I got good and comfortable with flying r/e/t electrics and built a Kadet LT-25. I was smart enough to get checked out on that though. The instructor took off, trimmed her out, and handed me the controls--after a few minutes he says, "you don't need me here, now let's see how you land." Still haven't crashed that plane (but I make up for it with some of my high performance electrics).