As far as accumulating stuff whether it be knives or anything else we especially like or have used and liked, this changes too. How much you use a knife (frequency) depends on your lifestyle regardless of age. But I think the bigger cutting jobs decrease as we get older and as a result if you are honest with yourself, a small knife works perfectly well. But I still wouldn't go as far as to say "any small knife will do". I think we get smarter and more practical as we get older in terms of navigating our world. Certainly priorities change.
But if you admit that bigger cutting jobs decrease as we get older, then why won't any small knife do?
Certainly that stage of life where we're retired, taking easy, doing some traveling, we're beyond the Jeremiah Johnson and Rambo fantasies, and certainly well beyond thinking we need to carry something capable of taking out Chinese sentries while whispering "Wolverines".
As we go about our life, fishing, doing some odd small projects out in the workshop, taking walks in the woods with the better half of almost a half century, any small knife will do? Whats the difference of carrying a old well worn Buck 309 companion, or a Spyderco man bug, or a Victorinox classic, or a Boker pen knife? Does that piece of twine on the tomato plants know its been cut with a number 4 Opinel or a Spyderco ladybug? Or even an old Christy knife?
I've found that in my life as a retired old fart, any sharp piece of steel an inch or two in length seems to work. I've opened all kinds of packages with a Victorinox classic and the blade on a Leatherman squirt. Certainly that accursed plastic blister package doesn't seem to care if its been cut open by a particular blade. Heck, look at how much real heavy duty work is done by the blades on a Stanley 99 or a Husky or a Milwaukee utility knife with replaceable blades. The utility knife blade is all of one inch long when fully extended, and razor blade thin. Yet it cuts tar paper, drywall, insulation off cable being spliced, unboxes water heaters and other heavy stuff. When dull, it just gets reversed or replaced.
The ugly truth is, for the average suburbanite, any keychain size knife will do. In our pre-packaged, office cubicle, air conditioned world, theres just no buffalo to skin, hostile Comanche's coming over the hill for our scalps. In fact, the whole knife market as we know it now is an artificially created market to save a dying industry; the pocket knife industry. In the 1980's it was almost dead.
Do you know how many knife companies were in America before WW2? Over a hundred. But after WW2, and the great migration to the cities by all the farm and ranch boys that had seen the world and weren't about to go back to daddy's farm and 'work the land", people started to stop carrying a pocket knife. The all move to he cities for good jobs and more money than daddy would pay them. By the 1960's the knife industry was in trouble. Buck introduced the 110 and it was a craze for while, but it stated to fade. Not much use for a large lock blade in an office cubicle. By late 1970's the industy was stagnant again, and even Buck 110 sales were down. Then a young business man named Lynn Thompson came up with a brilliant thing, The tactical knife that could be opened with one hand. Then a young guy named Sal Glesser came up with a different idea to sell knives, the serrated edge that would go through seat belts with ease. New companies jumped on the bandwagon and the one hand tactical wonder was born. By the late 1990's and early 2000's, it was the new craze in knives. If it couldn't be opened in a blink of an eye and de-animate a sentry it wasn't good for sales. The old traditionals faded away mostly, and companies like Cold Steel, Benchmade, Spyderco, took over the market. It was brilliant marketing and the Walter Mitty in the knife buyers spent a lot of money on over built knives that didn't really have a place in the office cubicle world. The office manager put out a memo that you couldn't shout 'Wolverines" when cutting open a new package of copy paper.
Now its fading a bit as many of the young knife buyers who have invested in the collections and are a bit older now, realize that they don't really need these knives in an urban or suburban life style. Heck, most of society doesn't even bother carrying a knife anymore at all. We're the weird ones, the 1% of society that not only cares about a knife, but is obsessed about them in an O.C.D. way. Heck, I'm still one of the obsessed and cursed. I can't imagine leaving the house without a knife in my pocket. BUT...and theres that three letter word...I've come to realize that it doesn't have to be much of a knife to cut what I need to cut. How much blade do I need to slice open a bag of mulch, or trim some fishing line?
Yes, when you get right down to it, whats left in the bottom the pot when its all boiled down, is that any little knife will do. An inch and half to two inches will get you through the day in modern suburbia. Of course, if some howling Comanche's in war paint comes over the hill, all bets are off.