There’s no more personal item than one’s carry on bag, and I’m going to make a controversial recommendation. I use an all aluminum one made by Halliburton, which has been around for almost a century. It’s made of solid aluminum and weighs nearly 12 pounds. So it’s enormously heavy. That’s equivalent to a gallon and a half of water. But no matter what happens to it, it protects the contents inside. So I use up valuable weight with this aluminum case. But I’ve had the same one for 16 years and it’s still as good as new.