I was putting in a big shower door last Tuesday. The glass was huge, way bigger than what I usually handle. I thought two clamps would be enough to hold it steady. As I was adjusting the frame, the glass slipped and tilted forward. I had to grab it fast before it hit the ground. My heart was pounding and my arms shook from the weight. Now I know to always use at least four clamps for large pieces. Please, if you're handling big glass like this, take the extra time to secure everything properly.
My 32 ounce growler shattered last year with only two clamps. The glass was way too thick for that setup. I learned the hard way you need at least three for anything over 20 ounces. It's just not worth the risk.