Deciding when to buy or sell

When deciding when to buy, I tend to look for companies with sound fundamentals (strong competitive moat, pricing power, solid balance sheet) that investors have overreacted to after 1 bad quarter. These companies tend to revert to the mean on the long term, as long as I give it sufficient time.

As for selling, I tend to sell if my investi6thesis about a company has changed over time, such as decreasing ability to become profitable, inability to innovate with the times, overuse of debt to finance growth.