a. Reduction/elimination of environmentally sensitive materials. Is it important to you that a machine meets the criteria set out in the EU's RoHS directive, which limits the usage of certain hazardous substances in electronics? Or perhaps you want a machine that exceeds those requirements, using even less lead, mercury, chromium -- as well as little to no PVC and hazardous flame retardants. The benefit here is to reduce the adverse effects e-waste has on the planet and people when it ends up in landfills.

b. Material selection. If you're an advocate of recycling and reuse, it might matter to you if the machine's plastic parts are made from recycled plastic, as well as renewable and bio-based plastic materials. These are certainly an Earth-friendly consideration.

c. Design for end of life. Beyond just the amount of recycled ma-terials that go into building the system, you might be concerned with how well the machine was designed for treatment once it's retired. The easier it is to open the enclosures and remove parts -- and the more reusable parts it contains -- the better for the environment. But it's also good for your company if you see the wisdom in purchasing refurbished machines. (See tip No. 5)

d. Product longevity/life cycle extension. Piece of mind comes with a multi-year warranty: It means the machine was built to last a while. Beyond that, consider asking how well the product was designed for upgrading. For example, was it built in a way that it's easy to swap in parts such as new memory or drives with common tools -- or even major com-ponents such as the processor? (See tip No. 4.) On top of the environmental benefits, those kinds of traits often result in cost savings, making it easier for you to invest in parts instead of entire systems when a machine becomes too dated for your needs.

e. Energy conservation. Beyond Energy Star compliance, you might find out whether there are chargers available for the system that draw on clean energy.

f. End of life management. When it comes time to retire your equipment, it's ideal if the vendor offers convenient -- and preferably free -- recycling services, be it directly or through a third party. Some vendors will even offer incentives on new equipment if you return their older gear to them for recycling.

g. Corporate performance. If you've made a commitment to protecting the environment, you may want to hold those you do business with to a similar standard. Some companies demonstrate this with a corporate environmental policy that meets certain international standards, as well as by producing annual reports on their environmental efforts.

h. Packaging. When you purchase a machine, you also have to deal with all the packaging. You might want to know whether that packaging is easy to recycle, or if the company will take back the packaging for reuse (or at least recycling).

4. Consider doing it yourself

After you've made a list of your needs, take a second look at what you've got. Do your systems really need to be replaced -- or would adding additional memory or a new graphics card do the trick? Depending on how many machines you have at your company (or home office), how well the machines are built for upgrades, and your comfort with do-it-yourself electronics projects, that approach might be not practical. But if you can pull it off, you'll save yourself some money and extend the life of your investment.

5. Go the refurbished route

Major hardware vendors as well as third parties sell pre-owned machines at the fraction of the cost of a new machine; thus you can save a tidy sum while doing the Earth-friendly thing. As with buying a new machine, you'll want to determine your computing needs and green criteria in advance so you make smarter choices.