I have often been drawn to minimalism. My definition is having only things that serve a purpose or bring you joy, clearing the way to let you focus on what matters. In particular, I seek two outcomes: reduced cognitive load and reduced decision fatigue.
When I read about minimalism for the first time, I tried things like having only one pen, a pen that I really liked. Or having only one, good quality comb. The idea is that with only one, cognitive load is reduced because there's only one to keep track of. And decision fatigue is gone, because there's only one option, so no decision is required.
I still have that pen and comb, but I also have other pens and other combs. The reason I bought more pens and combs was simple: convenience.
A lovely fountain pen is a delight to use. But if I need to make a note and my one and only pen is in another room, I have to stop what I'm doing to go get the pen. I added a dependency. I reduced the efficiency of writing that note. So, I was less likely to write the note down and I tried to rely on memory. This increased my cognitive load.
Having only one of a thing can add steps to a process, increasing the amount of yak shaving required to do a simple task. It adds a dependency.
When you have only one of a thing, there is no room for accidents or "what ifs", no keeping things "just in case". With most things, replacement is only a matter of money and time, and not having it is not life threatening.
But having to replace it means added dependencies. It means added time spent replacing it. It means money you didn't plan on spending. And, if your stuff is non-standard in any way, replacement may be more difficult: replacing a micro-USB cable is easier than replacing a proprietary Sony cable, and replacing "normal" sized clothes is easier than plus-sized clothes.
Put another way, having no backup means not being prepared. When I compare the stress of extra things vs. the stress of not being prepared, I prefer to be prepared.
Having only one of a thing means having no backup.
One of the traps I fall into after reading about minimalism, is trying to find the perfect thing. When you have fewer things, the idea is that you really use and enjoy that thing. So, if your only pen is a cheap pen that only writes after a few scribbles, it's not as pleasant to use as a good pen that writes the first time. From this, I tried to find The Perfect Pen. That quest led me to having multiple pens because The Perfect Pen for journaling is not the same as The Perfect Pen for quick notes.
The search for The Perfect anything is both stressful and a fool's errand. Unless you enjoy the search, that time is wasted - exactly the kind of thing minimalism is trying to avoid. And, there's often no signal for "good enough". Yes, a backpack might be functional, it might be pleasant to use, but is it perfect? There is always room for improvement, so the search continues.
Having things that bring you joy does not mean that everything must be perfect.
After I read about minimalism and start thinking about the stuff in my life, I eventually come to a balance. I have enough things and a backup. There is still some decision fatigue, but it is balanced with efficient action. I have things I like, but they need not be perfect.
The lessons of minimalism are good to examine now and again. I enjoy my stuff, but I recognize that the stuff itself doesn't bring me happiness. Stuff is enjoyed by my interactions with it. It reminds me to focus on what matters in life and not on the stuff I use when doing those things.