Well this read has been pretty lively. I used to jump right into these with my opinion. It seems I always got scolded so I just stopped. I'm sorta surprised this thread hasn't been locked already. I like it when the site was more ruckus.
Zane used to say, "Talk to each other like you are face to face. You might meet the person you are insulting someday. After to much insulting you won't even want meet the guy"
The answer to the question is, when your wing stops flying.
I have heard one real dangerous time as a pilot is around 500 hours. I think I read Tom was in that area.
We all get so much joy from flying, sadly when thing go wrong, flying is very unforgiving. Be careful my friends.