Should you buy an air conditioner?
#1 Scenario (best case)
You decide to NOT buy one and tough it out. And it turns out the there are only a few hot days. You didn't buy and you didn't need to.
You decide TO buy and the Summer is long and hot. You did buy, and it's a very good thing you did! You feel smart
You decide TO buy, but you end up not really needing it. You regret your purchase, but at least you have it for next Summer.
#4 Scenario (worst case)
You decide to NOT buy one, but it's the hottest Summer ever. You daily regret your decision, but continue to not buy one b/c you figure Summer will end soon. And you'll prolly do the same thing next year.