This is reminiscent of Benjamin Graham's "margin of safety" idea in investing. Get yourself in a position where you think the stock you want to buy is cheap and

This is reminiscent of Benjamin Graham's "margin of safety" idea in investing. Get yourself in a position where you think the stock you want to buy is cheap and certainly worth buying. Then buy it if it only if it becomes even cheaper. Put yourself in a position where you think you are unlikely to get hurt by a single mistake, and then insert an additional layer. So really it should be three :)