I’ve used a succession of pencil cases for pens/spare needles/emergency hypodermics/clippery thing/2 million used test strips etc. When they get too unspeakable grubby, I fancy a change, or the zip gives out I’ll go and pick a new one.
The testing kit doesn’t quite fit so that sits on top which is a bit of a pain, but not enough of one for me to do anything about it for the last 20 years.
More often than not if just nipping out to eat I’ll only bother taking the pen shoved in a jacket pocket.