Close vs. wide bench-press grip: Why does so much fitness advice contradict itself? (slate.com)

First thing I can say is what a rag Slate Magazine is This is the first article I recall ever reading on Slate that wasn't biased and FOS.
I subscribe to this theory. Unless you're a World class athlete whose livelihood is make or break by 1/2 kilo more, it's academic. I can give a dissertation on grip width. Short version: what works for you is what works. Everybody's different. Discriminatory, I know

Well, according to Christie Aschwanden, an athlete, science journalist, and author of Good to Go: What the Athlete in All of Us Can Learn from the Strange Science of Recovery, we’re anxious because we’ve all been taught to ask the wrong questions about fitness. As it turns out, the process of getting in shape doesn’t need to be complicated at all.
“People have been convinced that we need to optimize everything. That there’s this absolutely optimal way to train that’s going to get you the best results, and if you don’t do that exactly right, your results are going to be subpar. It turns out that thinking is almost entirely backwards,” she said. “Basically, any kind of exercise is better than none. So much of the benefit comes from just getting off the couch. If you’re interested in strength training, you can find all sorts of advice that is extremely specific in how many reps you need to do, how much weight you should put on, and how much rest you need to take in between. But really, most of the benefit is simply in the act itself.”
Aschwanden is illustrating the essential paradox in fitness science. Exercise, in almost all capacities, works, so any of the optimizations she speaks of—the wave of ink spilled about barbell grip or squat posture—is only going to augment your gains around the margins. “We’re bombarded with the idea that there are certain secret tricks that will get you a better workout,” she explained. “It really doesn’t matter that much if you’re doing five sets or two sets, or if you’re going to the gym five times a week or three times a week.”
Case in point: Aschwanden cited a study published in Medicine & Science in Sports & Exercise that divided participants in a strength training program into three groups. One group did only a single cycle of the exercises each session—deadlift, leg press, and so on—while the others did three cycles and five cycles, respectively. Those who worked out more reported larger visible bulking to their thighs and elbow flexors, but everyone studied had made equivalent gains to their overall strength despite the difference in reps. That’s because—to Aschwanden’s point—all of them took the most important step: leaving the house and hitting the gym.