My husband, Alan, never wears a sgian dubh for everyday, mundane, non-Scottish/Celtic-focussed activities -- and as a result, he usually forgets to wear one even in the Celtic venues. It's the most anachronistic part of Highland attire, and if you want a handy knife, a Swiss Army knife in your sporran is probably a better choice -- though we do sell a sgian dubh that has a fold-out corkscrew, bottle opener, and screwdriver! (If you want a knife for self-defense, you have other issues beyond the scope of my post!) These days, it's often better to leave the sgian dubh at home -- even a safety sgian dubh, unless you want to get stopped by security and possibly lose it. Even without a blade, they are hard and sharpish, and could be confiscated just because they look like a knife!