In June, when I began thinking about how (and why) the pen was performing so well despite my thorough disregard, I took a closer look at its design. The first thing I made note of was the o-ring that seals the cap thoroughly in both the capped and posted positions. The second observation (thanks to the fact that my Mini is one of the clear demo models) was that the inner cap seemed to sit completely flush against the "swell" of the feed just above the metal ring of the section. This led me to wonder if the folks at TWSBI had designed the cap/inner cap/section to hermetically seal the pen's ink supply from outside air (and thus prevent ink evaporation and nib dry-out)?
I dashed off an email to Philip Wang with both my questions and speculations -- and he very generously wrote me back with answers. Philip said, "We've achieved this air seal in 3 steps. 1st step... the inner cap within the cap. That seals out the most. Then comes the threaded barrel. Most fountain pens don't thread the cap on. You clip the cap on. Clipping is convenient, however, it lets air through. Threads act like blocks... to keep air out. The last part is the rubber ring." He added, "That's more of a preventative measure.... It's not really necessary for it to be there, but we feel it gives a better feel to the capped pen, and it helps a little with the seal."
Well, at the 3-month mark my pen was doing fine and I was still preoccupied with family matters. So, I let it go. At four months things are finally returning to normal and I can once again share a post with you (and report that the pen is still doing fine -- writing first time, every time I uncap it, without hesitation). I still have a little ink left in the reservoir, and things are still just hectic enough that I'm not prepared yet to return to a routine of weekly ink rotations. So, I think I'll let it go for another month (or until the ink runs out. Expect a final update then (perhaps followed by a similar test involving Platinum Carbon Black pigmented ink).
And thanks again to Philip Wang and the folks at TWSBI for giving us yet another reason to love this very forgiving pen.