For years when I traveled where I couldn't carry a gun, I would take along a folding knife for protection. I now know better. While convenient, folders are difficult to deploy under stress, and the spot where the blade pivots is inherently weak. This disqualifies them for serious self-defense work. Instead, invest in a good fixed-blade knife. But do your homework before strapping on a blade. State and local ordinances governing knives--both fixed-blades and folders--are varied and confusing, so take time to investigate the laws where you plan to carry.