So I am a history buff. Or, if I am being honest, a history nerd. I especially like military history, and I especially like WWI. Everyone is familiar with the Gillette khaki sets, and I know there are several Ever-Ready army models. Or at least variations in the pouch construction. And just the other day, I saw a Valet army set! That one surprised me for some reason. I like Valet razors, but I would be kind of bummed to have one in the trenches, while my buddy was using his Gillette. So, is that it? What razors are available in the 'army' configuration from WWI? Did any foreign companies make a similarly conceived, battle dress friendly, safety razor?
I haven't got a clue. But I'd rather have a Valet in the trenches than a Gillette. With the Gillette you need new blades every so often, while the Valet strops its own blade. Therefore no need to worry for a sharp blade. Now as to staying alive...
My guess, and it's only a guess, is that most (?) of the WWI shavers used either strights or possibly wedge-blade SE razors that could be stropped.
And in a pinch you can use the strop as a gag or tourniquet. I have not yet ventures into those sets, but I do enjoy looking at them.
That would be the immediate thought... but when you are up to your knees (or higher) in mud, I would prefer to slap in a blade, buff the razor off on my sleeve, shave, and get back to hopefully staying alive. As opposed to a razor that features delicate gears in its function, let alone finding somewhere to hang the strop so you can pull it tight, etc. After all, the marketing of the Gillette razor to the army in WWI is a big part of the companies legendary early success. Note that Valet didn't get the same boost in sales post war.
