Sorry but no. It ALWAYS makes sense to sell high and buy low, even if you're buying the exact same company. In other words, just find one value play if you want, and follow the cycle.

The skill is in determining what high and low is - i.e. you do need to have a sense of what the asset is worth. The easy answer is - figure out what its worth to you. i.e. what level of earnings or dividend does it seem attractive, and then accordingly, what is too cheap and what is too expensive. Obviously, take into account debt and other liabilities if you can.

That's why its necessary to understand the basic business model.

The tricky part is the temperament to do nothing when others are in a frenzy. Only a few transactions in your entire lifespan will determine the vast majority of your performance.