Thanks for the input folks. If you have not seen the training section of the Aiki Web there are a few good arterials on the subject of age, health and training. This one I wrote a few years ago http://www.aikiweb.com/training/hooker5.html
One of the questions I may not have made clear enough in asking "When is long enough to long" is, is there a lack of parity in recognition. Some Americans (again I am not experienced with other countries) have trained in their various arts with a specific instructor two or three times longer than that teacher studied with his sensei. Some of these people are really talented. Yet they never seem to reach, or are given recognition for reaching, the same height as their teachers. Even though they may have actively trained under strict supervision two or three times longer than their teacher did. As for myself I have gained more than I ever believed possible, but I have friends in various arts that have not received the recognition and I believe respect due them. Of course their evaluation of their situation and my concurrence could be wrong.