Most bridge players know that you can make a major suit game with combined partnership holdings of 26 points and eight trumps. (Plus the absence of "bad breaks" in trumps, finesses, etc.).
My observation is that one usually can also make such a game with 23 points and nine trumps and 20 points and ten trumps. Put another way, an extra trump is worth a king. (Take 40 HCP divided by 13 tricks= 3 1/13 HCP per trick. One "long" trump is worth a trick, by definition.)
I believe this is the basis of Larry Cohen's "law of total tricks." What is (Larry Cohen's) the "Law of Total Tricks" In Bridge?. Which other experts have systems that seem to follow this principle.