Investing or speculation are two very different ways of thinking. If a person sees the asset valuable and want to hold for a long time, he would like to buy it at the right price and hold it for a long time until the value is not worthy in his opinion. If a person is not sure about owning the asset while he is trying to guess its price will rise or fall and trying to profit from that, it is called speculation.
A lot of people think the stock market is volatile, and it is easy to lose money. I am asking him this question: do you think the stock is worthy? If yes, buy it with smaller amount of money over a long investing period. This way you can smooth out the volatility of prices. And you hold it until your opinion changes. If you are trying to time the market to buy low and sell high, you are more like a gambler, because nobody knows it will rise or fall tomorrow and you are not smarter than all the people trying to gauge the price. The price is hard to be “right” at any moment, because it is all about supply and demand.
This strategy (dollar-cost averaging) is particular useful when investing with index which is diversified to eliminate individual risks. If your answer is yes when investing the US market, using the strategy can help you earn market return.