Ah, the big dilema as I get older. I love cliff jumping but above a certain height, it's just not worth it on my back anymore. I've never gotten hurt except for some ass bruises, but I can tell it does a number on my spine. I usually only go big in lakes where I can see 15-20 feet down. I only jump in rivers anymore at known cliff jumping spots. I jumped off the south canyon bridge once and just brushed a rock under the muddy water. That was stupid.
Has anyone noticed the higher you jump the less deep you go once you hit? Above 80 feet is seems like the turbulence when you hit is so great you just maytag in the upper 5-10 feet of water.
I never jump with a life vest but have comtemplated it after hearing about my brother-in-law getting knocked unconsious jumping from a 60 feet bridge. Rather than looking staight ahead when he hit he kept looking down and took the impact on his face. There are also the posters at Lake Powell stating that it is now illegal to jump and showing photos of a guy getting knocked unconsious. They found his body a hundred feet down. I don't know how much of a risk it is getting knocked unconcious if you have proper form, but then again it's when things go wrong that you need the backup protection.