The markets go up and the markets go down, they are unpredictable. The gains you make today may evaporate the next day. The markets have been on a roll last five years, will it continue, nobody knows. A lot of stock price movement happens after earnings are reported by the company. So if you just play for after earning price appreciation, you can avoid the market volatility. If you select strong companies to invest in for after earning, price appreciation, in the long run you will make a decent profit.
I have started a website to identify strong companies that you can invest for an earnings surprise.
Disclosure: The author is long ECOL.