Invaluable bit of kit!
Having a file kit to keep your tools sharp in the field is a must! Especially in a long term situation where enough time goes by that one could really do some dulling!
Not only for the obvious reasons of touching up your favorite blade, axe or machete, but for the not so obvious reasons like hardened steel makes a good flint striker and it allows you to do some moderate shaping on bits of metal material you may have found scavenging for resources!
Include a 4 in 1 rasp for doing some mild wood working and maybe even modify a file or two with a chisel tip for making notches, holes and some extra assistance when carving bowls or cups!
Triangle file for sharpening your saw or maybe getting in those hard to reach corners! The pointed handles can easily be shaped to punch through hides and leather while still remaining functional for fitting a proper wooden handle!
Throw in a round file for serrated edges, notching scrap metal or sharpening a scoop knife!
All can be cut down to reduce weight and stored in small roll pouch to slip down in your bag, boot or cargo pocket so you’ll always have that invaluable bit of kit when you need it most!