The only thing you should wrap around your neck and shoulders are Kiwi coils, meaning no slings. The reasons for this are many: safety and practicality, the classical image: a climber festooned in slings, pretty outdated. The reason for carrying slings like this in the past, was due to slings being thick and heavy, with ten modern 8 mm Dyneema slings weighing the same as a single 1980s 28 mm Troll Supertape sling. The stiffness and thickness of these old slings, as well as very large stitch patterns, meant carrying them over the shoulder was the only option The crisscrossing of slings often lead to problems when a novice, especially when using axes with leashes (you’re hanging on an axe you can’t let go of, but that’s the side your only sling is on). 120 cm slings were generally clipped into themselves, so you could more easily remove them (like a snake sling), and you still see this in common use. But the biggest problem was with packs when you’d end up wearing it over your slings, or cross them with a chest strap; then there was the issue of slings getting hung up on headtorches (and pulling them off), as well as when carrying coils. These problems often led to climbers just putting the sling around their necks; not good. I only know of one climber who was straggled by a sling, when he jumped down off the end of a rap rope that didn’t reach the ground, but ended up hung up instead but has got hung up by a sling myself and suspects many others have over the year. Now slings are 11 mm or 8 mm and shoelace light, and 60 cm slings are generally racked as draws; 120 cm and 240 cm bundled up and clipped to the back of the harness (carrying a 7 mm cordelette rather than a 240 is maybe better for most climbers). Yes, some carry heavy nylon sling because they’re ‘more dynamic’, but the reality is that pales in comparison to how undynamic you are when tangled up in a sling.