If you ask most investors, you’ll find that they love to buy on weakness. They want to buy a “good company” after the stock has fallen 10%, 20% or more. A few investors, on the other hand, like to buy strength–they want to buy a stock as soon as it breaks out of a range, often into new-high ground. (The phrase “buying strength” always reminds me of Carlton Lutts, who founded our company decades ago and successfully ran Cabot Market Letter until just a few years ago. He told me that, back in the 1960s, when Chrysler was a...