I have written many times before about questioning what you use, as a way of finding the best tools available to do what ever you are trying to do. But I have left one very important slot open, and that is when to do it.
It is very easy to buy every single new and shiny thing out there, just because they are new and shiny. But that is just a very simple way to spend a lot of money, and fill your house with a lot of crap you'll never use. The alternate approach is to let the need come before, you buy it; instead of trying to find a use for something after you buy it.
For me, everything stationary I order are in one of two categories: new stuff and more of what I already use. What I mean by more of what I already use is things that I need more of(inks, refills, notebooks etc) and things I need to replace, like pens. While new stuff are new pens and other items that I buy to solve a specific problem.
Let me begin with new stuff. I don’t order anything the first time I see them because I know that it is a fairly big chance I won’t use it much unless I have a plan for what it is going to solve for me. But I add everything interesting I see to a list, so that I have a good place to start when I need something to solve a specific problem. And when I decide to buy it, wait a few weeks to see if I really need to pull the trigger. Some problems aren’t big enough to actually justify it, while others are.
The tricky part is when you want more of something you already own and use. For example inks or notebooks. It’s okay to have a few bottles of ink or a nice pile of Field Notes. But you should in general avoid ordering at a higher pace than you are using. My strategy have always been to order a pile of refills for my Travellers Notebook or a pile of Field Notes and then wait until my stock is almost out before I order more. And seriously: how many bottles of ink do you need? When you are getting close to owning more ink that you can use for the rest of your life, is the moment where you should stop buying; and maybe selling a few bottles before you order more?