Interesting. My 1915 Vega has bar frets, as does every other instrument I have ever seen from that era. Generally, most fret wire is fairly hard and a good compromise between wearing frets and destroying strings. Fret wear varies a_lot_from one person to another, depending on the strength of their grip and their personal body chemistry (this affects string wear too). I don't seem to produce heavy fret wear myself, but I know people who need new frets every year or two. Basically the frets that you get from suppliers like Stew-Mac and Luthier's Merchantile are about the hardest you can find.