That definatly depends on the specific planes ability as well as yours the piliots. If you have a Cap or Giles that tends to be snappy and needs airspeed to recover then you need to be much higher than say a profile plane that can recover in almost a stalled state and doesnt know the meaning of the word snap. I consider myself an accomplised piliot and my giles couldnt be below 75 ft and have a mistake yanking on the sticks only made matters worse. Where as my Morris Knife I have hovered 12ft above the ground and gone dead stick flipped nose over tail and flared and landed it perfectly. To me that was a mistake high. Its definatly all relative to the plane as much as it is to the piliot.