Been to war. If your unit has a good supply sergeant everybody gets a blade. If you work in a cage you can't carry anything. If your running MSR's, you have ton of shit on you an in the truck. Foot patrol, truck (MRAP) in overwatch has the extra gear, you'll have your primary load plus extras, gerber/leatherman, benchmade seat belt/strap cutter, SAK, clip folder an if the CSM or Top allows it a fixed blade (other then issued). If your a Fobit, you have a knife in every pocket, nice new autos that my supply sergeant ordered four months ago, f'ing thieving Fobits
Coming home is fun. You carry your firearms home on the plane. But the blades have to be locked in the hole (contracted commercial). Customs is fun also, you may loose your blades there
Mission dictates what you carry. 90% have a gerber/leatherman, depending on age 50%-70% have a SAK (I gave 104 to Soldiers in my unit), 80% have a clip folder.
What folders I carried on deployments:
1) SAK in left pocket.
2) 1986 issued Leatherman, broke it in Camp Cropper 2003, issued a Gerber broke it in one week, issued another an another ...
3) Spydie C01 Worker, Chinese Lum C65, Gen 1 Police C07 (stolen by a 42A, God help that Private) an cheap local folders.
An a strap cutter an fix blade on my gear.
Hell, you need a knife just to open your nasty MRE's (or clean your weapon).
Only carry what you are willing to lose, break or give away. One or the other will happen.