1½ years ago, I had the front tire on my Panamerica wash out in some sand over rocks on a forest service road, and it threw me into a rock, breaking 3 ribs, partially collapsing a lung, and partially separating a shoulder blade. 6 months later, while on my Bonnie, an asshat came at me head-on while texting on his phone, leaving me no choice but to hit the curb- landed on those same ribs. Of course, he didn't stop. Shortly after, I bought an Alpinestars Tech 5 Air Vest. Yeah, it's a little toasty when it's 100°, but at 77, this old bod can't take any more hits like that. I went for the algorithm type for reasons mentioned above. Got a great deal at Chromeburner. I wear it every time I get on the bike, in addition to ATGATT- jacket, pants, boots, and gloves, helmet.