A long-time reader and portfolio-management client recently asked a question that other investors may wonder about in today’s turbulent markets. He wrote, “You constantly remind members to have a balanced portfolio and strategy for long-term success when investing. But when do you take profits? You have mentioned a couple of times to sell, such as when a stock makes up too much of your total portfolio, or if a company shows questionable management or business decisions. My main question is why don’t we sell when stocks move up and there are profits to be had?” I often asked myself that question in my first decade or two in the investment business. In hindsight, it always seems easy to spot market tops and market bottoms. But trying to spot those tops and bottoms as they occur is harder. I investigated all sorts of market theories and signals that purport to tell you how to do it. They all seem to have “worked,”…