The oldest knife that I have and still use is my Friedrich Herder working knife, I own it for about 15 years now. It is strong and it did the job it had to do, so for many years I didn't need an other knife. But it was not really an EDC knife, it was for working. The EDC knife that I have carried most is my Victorinox Soldier, until I got into knives and bought more SAK's and some other knives, mostly working knife types. Now I'm rotating between several knives, I always carry a SAK, because for me it is a very useful tool.