I recently found and enjoyed this thread against small-m minimalism, and how globally, we're losing a sense of character, detail and identity in objects and places. Although I agree with all the examples proposed here, I still want to make a case for purism as a way to simplify one's individual life.
Not unlike minimalism, a purist approach to life brings a lot of simplicity and reduces the mental energy required to make decisions. The dictionary definition of a purist is "a person who adheres strictly and often excessively to a tradition". And Urban Dictionary describes a purist as "someone who prefers the old way of doing things" or even better, "a person who you'd get into an argument with on a forum". To me, purism means sticking to the purest, most natural form of any one thing.
For example, in materials. Furniture makes the most sense when it is made of wood and the grain should be of a natural shade of brown. Denim is meant to be some fade of ecru (white) or blue. Linen is naturally an off-white beige-y colour. Exceptions abound here; I've had my fair share of coloured denim when I was younger, and I would still choose my plastic, metal and fabric ergonomic office chair over any wooden seat for my butt to spend that many hours on.
Coffee is meant to respect some kind of tradition; an espresso, French Press, or Moka Pot, not much else. You only need one wristwatch and it only needs to tell you the time. Belts work best when they're made of leather. Purism helps you make decisions when shopping but also in many other aspects.
Having adopted the Apple ecosystem, I choose to stick to the native apps as much as possible. It prevents me from having to struggle with Chrome slowing down my whole machine, or something not syncing to my phone or tablet. Although I'm all for open source software, it's nice to have a "rule" to default to.
Purism is having in your kitchen the accessories most likely to be found in the greatest number of households. Purism is finding the nail polish that suits you best and sticking to it. Can't go wrong with white for all seasons and all skintones.
Purism is sticking to the "textbook definition" of things.
Picture a chair in your mind. That should be the general shape of your chairs. Now, I have nothing against people who collect eccentric designer chairs, purism is not about restricting passions, but it's easier to shop for a textbook chair than to find the most unique and different one out there.
What makes up a bed? Two pillows, two sheets and a covered duvet. Not much else. What makes up an at-home desk? A computer, a couple pens, and something to write on. Not much else.
Of course it's easy to argue that such a life doesn't suit all tastes. But it has high chances to. Purism is about not reinventing anything, sticking to what works, what's worked the longest, and for the greatest number of people.
Purism is about embodying the human life "by definition". This might sound mediocre and not exciting, but it works wonders and I'm lucky that it suits my personal taste.