How much ink is in a pen catridge when it starts to fade?

Sorry for the weak subject line.

Okay, my concern is about my pen cartridge. Let me brag about having the Squire by Baron Fig. It uses a standardized cartridge:

You can grab more refills right through our site, or find any compatible refill that fits the dimensions of a Schmidt P8126.

My issue is about waste and recycling. I will figure out the best, if any, practices for recycling these things. I hate to be defeatist about it, but I mean, I am not going to stop using a pen. It would be more likely I start a cartridge recycling system if one doesn’t exist.

What I am new to is refilling my pens at this level, and I have questions about that. Specifically, what is the rate of writing degradation from low ink?

I noticed my pen stopped writing as boldly or deeply, seeming to output less ink. Ya know, as pens do. But I thought it would run out soon. It just kept on writing, but more and more faded. I could see it from flipping the pages in my notebook, as we approached the current section my writing seemed like it had aged and faded… a nice sentiment on the transient nature and space and time, but I need my fucking pen to work! :slight_smile:

I switched it out, and wow am I glad to have a fresh cartridge. But the refills are metal, and I don’t know how much remains inside. What if I just threw away half the ink?! :sob:

Any insight into how that works, and what the most responsible use of resources is in this scenario? :thinking: