What is Reliability?
Reliability is the ability of a system or component to perform its intended function under specified conditions for an extended period without failure. A reliable product has a high probability of performing as expected over time. The reliability of a product can be measured by how long it will last before failing and how often it fails.

In other words, a reliable product does not fail. It performs consistently and predictably.
The following are some examples of products that have been designed with reliability in mind:
- A car engine that starts every time you turn the key.
- An airplane that flies safely through turbulence.
- A medical device that works properly when used on patients.
- A refrigerator that keeps food fresh.
- A telephone switchboard that connects calls correctly.
- A nuclear power plant that operates safely.
Reliability can be improved by designing products and systems to reduce the likelihood of failure, using high-quality materials, and conducting thorough testing and maintenance. Reliability engineering is a field dedicated to improving the reliability of products and systems through the use of statistical analysis, root cause analysis, and other techniques.
Conclusion
Reliability is one of the eight dimensions of product quality defined by Garvin.