Mr. Hallvard: = As a cardiac surgeon, I have faced the same decision. What I found most helpful was to ask the opinion of my colleagues. If asked, they will glad= ly tell you when they think it's time. I stopped doing cardiac surgery in 19= 88 at age 58. I continued with thoracic and vascular surgery until age 62, then fully retired. = I too ran the pump-oxygenator system for several years during my residenc= y (1963-64). How things have changed since then! = Best of luck to you! Mitch care-partner for Betty 15/67.