Sea changes in global markets don't happen often but they may be the only times that matter in an investment career. Knowing when and how to avoid risk, and when and how to take it, will determine the long-term success of any investment programme. The older I get, however, the more I understand T.S. Eliot's great exhortation from his poem The Wasteland: "Teach us to care and not to care, teach us to sit still." The worst temptation is moving too quickly once a market has begun to shift.