Founders should calculate what they're risking by NOT selling. It's easy to look at an acquisition offer and think... What if I hold for another 3 years and the business is worth twice as much? Maybe it will be. But customers can leave. A competitor can pop up out of no where. Technology can change fast. Growth can slow down or churn can spike. You can also just get tired of running the thing. Keeping your startup is a bet on the future just like selling it is. Sometimes taking a few…