On exercises like the bench press or squat, it’s obvious when you’ve gone to failure. But on an exercise such as a lat pulldown or cable row, what is considered failure? I could continue doing lat pulldowns so long as I can pull down a couple of inches (to greatly exaggerate the point). On the other hand, just because I can’t get the bar to my chest may not necessarily constitute failure. With a cable row, similar–I could continue to pull out even just inches rather than the initial range of motion.