The Dow Jones industrial average hit a milestone in April, as solid earnings, merger talks, steady interest rates, and subdued inflation pushed the blue-chip gauge above 13,000 for the first time. The Dow rose in 23 of 26 sessions, marking the longest bull run since 1927.

Though Dow 13,000 caused many investors to cheer, it left some pros scratching their heads. "Good news is being embraced and bad news is being brushed aside," money manager Michael Farr quipped as he watched the Dow Jones industrial average claw above 13,100 for the first time on April 25. The founder and president of Washington D.C.-based investment firm Farr, Miller & Washington points out that there are three stages to any up or down market: denial, acceptance, and then exuberance or fear. "I don't think this is exuberance yet. I think it feels good, and it has a good buzz," he says. "But I'm feeling kind of old and stodgy because I'm thinking the hangover is really going to be ugly when it comes."

So what should investors do in the post-13,000 era? Is it time to buy stocks hand over fist, or time to take the profits and run? No stock market analysts or financial planner knows where the stock market will head next. However, Farr says the sectors that have propelled the market are past their prime, and new groups will have to emerge to fuel the rally.