Good for the environment, and less expensive. How often does that combination come along?
We benefit the environment by reusing post-consumer computers that would otherwise be destined for recycling, which generally involves melting them down for raw materials.
Manufacturing a computer consumes more energy than running that same computer over its lifetime. Adding 2 to 3 years of life to a computer saves 5 to 20 times more energy than recycling.
In terms of harmful chemicals released, it is roughly 25 times more beneficial environmentally to reuse computers than to recycle them at 3 to 5 years.
All of this adds up to some great PR messaging for you to present to your customers. (You don't have to tell them you saved money too.)