Pen mechanics when the cartridge is nearly empty

Pen mechanics when the cartridge is nearly empty — setting out what I have, and where I think it stops being reliable.

A question about technique rather than about dose.

I have been doing the same thing for 18 months and it works, and then I read one of the documentation pages here and realised I may have been reasoning from a misunderstanding the whole time. Nothing has gone wrong; I would just like to understand why it has not.

What I do, exactly, is described below. Please tell me which parts are load-bearing and which are superstition.

Picking up the opening post: that is the part I would want checked first.

Dose counters: pens show the remaining number of doses. When the counter reaches zero, the pen is empty and cannot deliver more. Noting the counter before injection prevents running out unexpectedly.

Pen mechanics: most pens are dial-and-inject devices where you dial the dose on the pen and push the button to inject. Understanding your specific pen's mechanism prevents dose errors.