One-liner
Picking a strategy and sticking with it usually beats trying to guess the moment to switch every time a new headline lands.
Why it matters
Trying to call the top and the bottom is a recipe for getting hurt: you either watch the market run without you, or ride it down far harder than you expected.
Analogy
Timing your entry and exit is like trying to catch a falling knife. The odds of getting it right are tiny, and you are almost certain to get cut.
The catch
Timing is hard even for managers with twenty-plus years in; for an individual, with a big information disadvantage, harder still. Michael Burry shorted US housing and was right, but it took so long to play out that he bled huge losses for over a year first. Even being correct, the payoff was not what the size of the call suggests.