Using a thinner font can save printer ink

[Kraker]

To a standard user, this difference isn’t big enough to care about.
But if you use a lighter font with thinner lines, you’ll use slightly less ink. This is all based on inkjet printers that use old-style cartridges.
Overall, it will only save you about 10% of your ink by using a lighter font.

 

[tts.alexius]

Totally agree, using a lighter font might not seem like a huge deal to most, but if you’re printing a lot, every little bit counts—especially when it saves you some ink and cash in the long run!