Apple (NASDAQ:AAPL) has announced that CFO Peter Oppenheimer will be retiring at the end of the company's fiscal year at the end of September. Oppenheimer has been with the company for 18 years, acting as CFO for the last 10. He will be replaced by Luca Maestri, who joined Apple last February as its corporate controller after leaving his position as the CFO of Xerox.

In this video from Tuesday's Tech Teardown, host Erin Kennedy and Motley Fool tech and telecom bureau chief Evan Niu take a look at the most important things for investors to focus on whenever a company goes through the changing of the guard in its top brass. Evan also takes a look at Maestri, and gives investors one key thing he'll be watching for from the new CFO from here.