So you already print double-sided or reuse single-sided prints? You can go even further in your quest for eco-friendly printing.
A font has been developed that reduces the amount of toner used while minimizing loss of readability. The download page includes tips on how to install on a variety of platforms, and here’s a tip for installing a font in Windows 7. Note that after clicking the “Install” button for a font, there is no indication of success beyond the Install button becoming disabled — although you can open the Fonts control panel to verify success.