Faulty hardware a lot lately

I’m not sure why, but I have had a lot of service calls lately that resulted in hardware components having to be replaced. In the past couple weeks, I’ve replaced five sets of memory modules, a network adapter, three monitors, two video cards, and a hard drive. Fortunately, none of these have been on enterprise-level machines, but just on personal computers. It is strange, though, that hardware is going bad on relatively new machines. Four out of the five sets of memory modules were bad out of the box. I guess that hardware vendors are not going through rigorous enough quality testing before shipping out parts.