One could adopt other strategies to meet these strigent hardware requirements. Some pay more for higher quality equipment, betting that this results in fewer failures. Some rely on vendors for support. They select a responsive company with a good reputation for service. Knowledgable help is vital. Many prefer local support staff who are easily accessible. Thom Holwerda wrote an excellent article explaining why he picks iMacs for high availability.
I take a different approach. I use generic white boxes with all stock parts. Since computers are inexpensive I keep several on hand, along with extra parts. It’s easy to swap parts if necessary. PCs are highly standardized — if you acquire them with an eye to non-proprietary components. I open up and inspect every machine before I use it. (Watch it with laptops. Some vendors will mold their DVD drives to non-standard shapes or add proprietary plastic you have to fit on your hard disk to properly connect it.)
For my self-service approach to work, you have to know how to perform basic hardware problem identification. You don’t need to be hardware-trained. I’m not. The key is to be able to quickly identify common problems, because the hardware fixes are easy with a replacement strategy. A good problem ID procedure and a few rules of thumb are all you need. (I’ll share mine in another article if people are interested.)