You must have a very old Military.
The screws to the current Military (and all of the older models that I've seen) don't have screws that go into the G-10 itself.
That's where that whole "a knife must last" thing fits in. I have a very old Military, if by "very old" you mean 440V version, which, let's face it, isn't old at all. And the knife is falling apart because screws on G10 gave way.
But let's say all knives could be disassembled and reassembled for as many times as I like (and yes, the Manix has screws on both sides, but those still get stripped pretty fast, very shallow). The question is, is one key enough to disassemble it in the field? And the answer would be no for 90% of production knives. With high end folders disassembly is seldom needed, but it does happen. So Sebenza is obviously ahead in that respect, all you need is a single hex on your keychain, and you can open any Sebenza, large or small, classic or regular, with the same bloody key. For other folders, you may need a variety of keys, for some you even have to take the scale off before you can disassemble the knife itself (Al Mar SERE, Emerson Commander), which is prohibitive.
Now, I also have a very old CRK Sebenza. Flat grind, BG42 steel, and it used to have Chris' signature on the blade until it got worn out with use and sharpening. Pretty old. As old or older than the Millie, because they went from ATS34 to 440V to S30V, and taken apart more times than I care to remember. It's still in as good condition as the much newer S30V hollow ground one from 2005, which was never taken apart. What's more, I could pack it up, send it to CRK, and it'll come back with polished blade, new lug and newly blasted scales which will hide all scratches it has now.
That's what is so good about it. You can actually work with a Sebenza, and when it gets too messed up for you to fix yourself, you ship it to the spa, and it comes back fresh and ready for more. And yes, you can just buy another cheaper knife to replace a worn one, but like I said, I prefer the same knife. A knife that gets passed between generations, that type of thing.
So it all comes down to do you want to pay $350 now and have the knife stand a very good chance of still be in good shape 60 years from now, or do you want to pay $350 in installments of $100 for a number of knives, and 60 years from now have the last of the bunch falling to pieces? This is actually something I saw discussed on another forum, a 30 year old wanted a knife that he would KNOW would last until retirement 30 years later. Suggestions? Sebenza, Strider and a pair of customs.
And this is coming from a guy whose collection is 30+ Spydies, half dozen each of Benchmades and SOGs, a few Kershaws, etc., and 6 CRKs (large and small, classic and regular, Mnandi and Mark IV fixed). The bulk of my collection is Spyderco. And I have all the heavies, including Chinooks and Manix. And with all those Spydies, I *STILL* think that Sebenza is an excellent knife well worth the money. If your first Sebbie is a small one, you might think "what's the fuss all about" until you carry it daily for 3 months, then you'll want a large one, and carry that for much longer. And then you'll know why.