I spend a lot of time in the backcountry, I am also active army and spend a good amount of time in the field, therefore I really don't have a PSK as such, I have gear that I carry and use on a regular basis. As I use things I replace them. I have a number of things I carry in a camelback and various stuff in my pockets.
What 1 item, besides your knife, are you never without, multitools don't count, they are knives. For me it is my surefire Z2 or E1 depending on what I am wearing, it has got me out of plenty of jams.