Every day I carry a Vic SAK, usually the same one for months at a time, then I may carry a different one for a few months, and so forth. I don't do anything terribly messy with them but I don't baby them.
I almost never wash them, but if I do need to, then I just soak them in Dawn dish soap and hot water and then scrub them out with a bristle brush.
However, every few days I do spray the blade(s) and the can opener with rubbing alcohol and wipe them down, just to sanitize them a bit. I do use the blades for cutting food every once in a while. I keep the alcohol in a spray bottle for cleaning my eye glasses, so it's ready to hand when I remember the SAKs.