Manufactured products tend to have two spikes in their failure rate: soon after being put into service (manufacturing defects showing up when the product has been used a bit) and near end of life (parts are wearing out due to long usage). In the middle, the failure rate is pretty flat.
Monitors failing within 3 months suggests that you're seeing the infant mortality part of the curve. If a particular monitor lasts 3 months, it will likely last for many years.
Tangentially related, but still interesting: most people think hard drives have a bathtub curve when failure rate is plotted against time. Turns out this isn't true.
Schroeder and Gibson: "Contrary to common and proposed models, hard drive failure rates don’t enter steady state after the first year of operation. Instead failure rates seem to steadily increase over time."
