If you are like me, and don't have that many pens, and like to have them all inked up: then you need to rotate them. What I mean by that is to make sure that you use them all relatively frequently to avoid them getting clogged up.
You probably have some pens that you like more than others. I have three pens that are inked up at all times. The pen I use the most is my Lamy 2000, and I always move over to my TWSBI 580AL when that is out of ink, and I usually refill them all as soon as possible when the TWSBI runs out of ink.
My Pilot Metropolitan serves two purposes: a backup for when my other pens are running out of ink, and two have a metal pen that I can put in my pocket for the rare occasions that I need that. It is a fine pen, but it isn't the most comfortable to write with for longer periods and the ink capacity is a little bit low.
But, I still want to use it regularly to make sure it is in tip top shape. So what I do is that I use it as my primary pen until it is empty once every second or third time I refill my other pens.
The reason I keep it around, at least for now is for those times, when you are super busy and forget to ink up your pens when they run out of ink, and you need to have something to write with for the rest of the day; either at work or while studying.