This is a timely subject for my boys 2025 Elk hunt. I've always liked a min. of 4 with broadheads and 1 judo for grouse. Night before hunt loading up the quiver, he only wanted 3 + judo. Didn't want to argue with him, so let it be. First shot was frontal with great blood, but long track. After 1/2 mile caught up to him. Only had a small opening and he put a 2nd arrow through the hind end at long distance. Bull took a few steps and laid down. 3rd arrow was low due to range finder registering on a log. He goes to pull out fourth arrow....judo.. We were only 1/2 mile from camp where he had more arrows/broadheads so I ran back.
Luckily bull died while I was gone, but long story short, min 4! On surface 4 or more seems excessive, but $hit happens. I liked the comment about not leaving any slots empty!