There will be corrections regularly, and panic spikes occasionally. This is why an asset allocation of 100% stock is too wild a ride for most.
so most blend some bonds, some real estate, some overseas stuff. And dollar cost averaging - just plonking away money regularly, removes most of the drama. But don't expect your portfolio to give you 30% in 2013 and provide low volatility.
It's only market timers who worry about this stuff. Personally, I'd love a huge crash in 2016.