I'll forget my toothpaste more often than I forget a knife
toothpaste is a nasty tasting useless "modern" invention thing that causes excess tonnage, and holey teeths.
(our ancestors 200+ years ago didn't have it. They still had their OEM teeth - usually without holes.

)
While enough knives carried simeltaniously
may result in excess poundage, (much less poundage (or tonnage) than "toothpaste", however.) A knife (or knives)
are useful and
necessary in daily "life" ... for meat and tater/turnip eaters, at any rate ... be they young and hale, or like I, old, wore out, and decrepit.
A knife or knives are also quite ... "handy" ... for some recreational activities, such as whittlin' a caged ball, or a tent stake, chain ... with or without an attached ball, feather sticks, tree spirits/gnomes/trolls, or a sharp point on one end of a pencil ... and so on.
Admittedly, one might be able to get the same results whittlin' using their finger/tow nails, and teeth, but a knife (or knives) makes it
so much easier ... and enjoyable.
"In my day" a "he" person was more likely to forget his britches, along with house and car and/or motorcycle or (keyed) bicycle lock(s) keys (locking himself out of the house if he has auto locks) than his pocket knife.