ORIGINAL: foodstick

I am going to take a slightly different angle on this... To me there is no reason to ever let your flying skill determine when to quit. If you never learn to fly and you enjoy the building,hanging out at the field ...
What else matters? There really aren't any points or reasons to do anymore than have fun. That being said I hope you can learn to your desired goal. There are some great suggestions above...

I personally will probably keep building if I can't see the airplane any further away than the work bench..I will simply get someone I trust to fly it. Its all about enjoying ANY PART of the hobby..there are no real required parameters ...