If you’ve been in the investment business for 40 years, you’ve seen it all: Incredible bull markets and vicious bear markets. Periods of high inflation, low inflation. High unemployment, low employment. Housing booms and busts, a fed-funds rate of 20% (really) and 0.25%. Wars, recessions, bailouts, scandals, Democrats in control, Republicans in control—you get the picture. So whenever you run into someone who has been advising investment clients that long, through all that turmoil, stop what...