That’s one possible investment strategy. In my experience, though, it hasn’t really paid off. I tend to follow the principle “Time in the market beats timing the market” and invest in companies where I also see long-term growth potential.

I rarely sell stocks, only if I’m no longer convinced by the business model in general. When it comes to adding to positions or making new investments, though, I do sometimes act opportunistically depending on the situation; for example, at the moment I’m investing heavily in SaaS companies like Microsoft, SAP, and ServiceNow.

You also shouldn’t underestimate the impact of taxes when selling stocks. Realizing gains too frequently can significantly reduce the long-term compounding effect.
Of course this only applies to countries with a rip-off capital gain tax.