2013 was a bull market year, despite a series of near-disasters. The benchmark S&P 500-stock index rose by almost 30 percent, the largest jump in 16 years, while the Dow Jones achieved 52 closing records. Never mind that the collapse of the Greek government threatened instability in Europe and political intransigence brought the U.S. to the precipice, the evidence still pointed to a gradually improving economy. And slow and steady investors were the biggest winners, as straightforward “dumb money” strategies outstripped the more complex game plans of hedge funds. But analysts advise caution for 2014 — vertiginous gains can’t continue forever.