One of the most important aspects of fountain pens and what makes them so entirely awesome is that one pen can put out any color you put into it. A ballpoint is enslaved to its refill good, bad, or horrible. A gel pen only goes as far as its producer. A fountain pen can connect brands and colors neither manufacturer even imagined. The designer of the Pilot Capless certainly wasn't thinking about Noodler's super shading inks like Apache Sunset. Nor did the Nakata family imagine seeing their beautiful Platinum or Nakaya creations filled with Pelikan highlighter ink. Ink offers so many new combinations for pens and makes that pen ever new.
How we use ink is nearly as personal as our handwriting. Some people in the pen community try to pair inks with pens, looking for the perfect color combination that just seems to them to be the pinnacle pairing of pen and ink, never to be changed. Others like certain inks and like certain pens and so put those favorites together in different combinations. Some just like one or two inks and stick with their mainstays. I am none of those people. I do find great pen and ink combinations. I do have favorite pens (really liking my new Pilot Custom 74) and favorite inks. Neither of these, though, guide my choice of ink.
I'm of the firm opinion that if I bought it, I must use it, whether it's my favorite or not, whether it came free with a pen or I had it imported from overseas. To have 30ml of ink sitting around unused is detestable to me. I will sometimes lessen the quantity by giving samples away to friends, but I WILL USE ALL MY INK. So, in an attempt to give equal opportunity to all my inks, (which number somewhere in the 60 bottle range) I rotate through every single one of them. One after the next after the next, my only pause comes with certain inks (Noodler's Baystate Blue) and some of my more vintage pens (with which I'd rather not damage with dangerous formulations). So, I'm guided by what's next rather than what do I want next. This frees me from the agonizing decision of which of the 60 bottles of ink do I want to use in the next pen. This self-imposed determinism allows me to just move along. It quickens filling time and disallows me from overthinking things. It also brings about nice surprises when certain pen and ink combinations arise that I wouldn't have necessarily though of, say for instance my Edison Nouveau Premiere 2014 Summer Edition filled with J. Herbin Rose Cyclamin. It was a beautiful combination of bright colors. So I just go through my ink drawer bottle by bottle inking up the next pen in rotation.
I have two exceptions. All my ink stays in my office at work (it's a block away from home) so I bring one bottle of ink home. I rotate that bottle every month. The bottle this month is Organics Studio Laboratory Series #14.
On the whole I like to use converters. I don't mind the less ink capacity because I also have another pens around if I run out of ink. There will be times, though, that I will choose a cartridge just to free up some storage space in my bulging accessories case. Here is where the second exception comes in. Certain pens only take cartridges. I have both empty cartridges which I can syringe fill and many full cartridges. It is a little less determined whether I fill and use a full one. I choose that on whim. If I do fill the cartridge it's from the next bottle.
Monterverde Artista Crystal - Organics Studio Laboratory Series #14
Monteverde Poquito Medium Nib - Monteverde Black Cartridge
Visconti Homo Sapiens Crystal Fine Nib - Papier Plume Midnight Blue
Pelikan M200 Italic Nib - Noodler's Golden Brown
Kaweco Sport Fine Nib - Kaweco Blue Cartridge
Lamy Joy 1.5 mm - Sailor Jentle Apricot
Sheaffer Desk Pen Fine Nib - Noodler's Apache Sunset