This is investing 101 advice, but two items matter. First, develop an estimate of absolute (some say “intrinsic”) value for an enterprise, and let that be your guide. When you get a fat pitch (when a stock trades well below your estimate), be willing to swing. Constantly update your assessment using inbound information. Recognize that your investments are always just a series of trade offs. Sometimes, you don’t get a fat pitch. However, if sitting on cash is worse, take an almost fat pitch and be satisfied you did. Don’t watch your pot to see if it boils.