Investing in stocks has a greater chance of being profitable when an investor looks at it as a long-term endeavour. It is definitely a smarter choice to invest in equities for upwards of 5 years. It is fairly true that the longer you keep a stock, the more likely you will make some amount of profit from it. This is because –

1. Longer the period, lower is the chance of VOLATILITY affecting your returns

2. Power of COMPOUNDING makes money work for you in the long term

3. Given the long-term HORIZON, you have time to rectify mistakes, if any, with losing all of your profits.

However, just buying any stock and preserving it for 5 years or more NEED not always work in your favour. Stocks markets are dynamic and just applying one rule will not work. For eg: If you bought a stock, without adequate research, just because it is CHEAP, not focusing on its growth prospects and other parameters, then you are more likely to end up with the short end of the stick, no matter how long you hold the stock. So, looking at this idea in isolation is not the right way to go about it. If you have ticked all the parameters of buying a good quality stock, diversified adequately, and kept yourself updated about the developments of the companies you have bought, then your chances of getting very good returns magnify in the long term.