You never really know what is going to jump out and bite you. Two years ago my rope broke which resulted in my ribs separating from my sternum. I now change my ropes every year. Last May, I completely tore my rotator cuff and a couple of other tendons tricking(of all things). I was working out on Tonal, 4 days a week, and skiing the other 3 days. I was probably in the best shape of my life. Sure, you can try to minimize your chance for injury, but you never know what freak thing might be lurking. I thought about not tricking anymore, but I need that necessary evil for overall.