What do you do when your favorite pen runs out of ink?

Yes. 
~

I don't play favourites with pens. The others might get jealous.

Replace the refill.  I have used the same pen since the 80s; it's a Papermate Profile slim, perfectly weighted, and thin.  I have four of them.  They have been out of production for a long time.  There is only one company that still makes a refill that fits.

This post was edited by Thriftymaid at September 27, 2019 9:35 PM MDT

When my favorite pen runs out of ink, I dip it in the ink jar and refill it. 

I have several pens to which I'm partial, none of them were purchased.  TD Bank "gifted" me two of them and the others were sent from charities looking for donations.  When they run out of ink, I just throw them away because sooner or later, new ones will be sent.

I've always had a favorite pen or pens, too. IF  I don't already have a refill, I get one.  Only if that wasn't possible anymore, would I throw one out..unless something was wrong with it.