When your favourite inexpensive pen runs out of ink, do you toss it and go buy another one? I know I do this sometimes without even thinking, especially since more pens are so easy to come by around here.

But the reality is, that’s just like throwing away money.

(Not to mention, you can’t really recycle pens at this point.)

The beauty of refillable pens is that they are, well, refillable. Once you buy the pen, you never have to replace it unless something breaks. When it inevitably runs out of ink, you just pop in a new ink fill and go right back to writing, drawing, doodling, etc.

Think at how much money you save by refilling, instead of replacing.

We’ll use the Pilot G2 0.7 mm as an example.

It costs £1.48 from online, US$2.74 from Amazon (at 2 for US$5.49), and US$1.40 from Jet Pens.

Let’s say you are an extremely industrious writer, and you go through one G2 per month. In the UK, you could spend up to about £18 a year replacing your G2. In the US, as much as US$33.

Now, refills.

They are £1.15 at online, US$.65 at Amazon (at 2 for US$1.29), and US$.83 at Jet Pens (at 2 for US$1.65). Twelve refills per year would cost you about £14 in the UK, and up to US$8 in the US.

UK savings = £4 a year. US savings = US$25 a year.

And it’s not as if refills aren’t readily available. online retailors sell about 80 different types of refills, or a total of 248 when you take into account the individual colors. Zebra, Pentel, Uniball and Pilot are the top sellers, as you can probably imagine.

Pilot alone offers 23 different refills in an array of colors, including 15 color choices just for the G2.

Admittedly, figuring out which refill goes with which pen is slightly more complicated than just buying a new pen. But, retailers do their best to make it easy.

At most good online stores, all ink pen refills are grouped together by brand and ink type. Staples has an online refill finder. And Tom, over at Goldspot Pens, has even created a special site called, appropriately enough, RefillFinder.com for some of the higher-end pens.

It can’t get much simpler than that.

Oh, and we haven’t even talked about the less tangible benefits, such as being able to put a refill from one type of pen into the barrel of another in order to match the best-writing fill with the most comfortable barrel.

For example, I recently put an extremely smooth Pentel Vicuna refill into a very comfy Foray Onpoint to make what I consider a nearly perfect ballpoint pen (well, as close to perfect as a ballpoint can get).

(UPDATE: Speaking of Tom and Goldspot, he tweeted a link to a blog post that is directly related to this post: Using a Monteverde refill to improve a Lamy ballpoint.)

Plus, we all get attached to certain pens, even the inexpensive ones, that we use them so often, they eventually they begin to conform to our hands. Think about that one pen you reach for all the time, and how it seems to nestle right into your hand, as if made for you.

I have multiple Pentel EnerGels in my collection, but there is one retractable that is like that. I’ve used it so much, I can pick it out of a handful of matching pens just by touch. That one will get refilled over and over because it is never going in the trash.

The bottom line is, there are lots of good reasons to refill your favourite pens instead of replacing them.

And look at it this way…if you take a couple of extra minutes to buy refills instead of replacements when your pens run dry, you will eventually save enough money to buy yourself a nice, expensive new pen.

OK, now it’s your turn. Tell us what pens you keep refilling.