Wear-Out Failure Period
During the wear-out failure period, the failure rate increases due mainly to deterioration of the item through prolonged exposure to operating and environmental stresses, which may include:
• Insulation breakdown.
• Wear or fatigue.
• Corrosion.
• Oxidation.
Normally, wear-out failures are avoided by replacing an item, either on the basis of fixed life replacement or on-condition monitoring. Even so, eventually the system becomes troublesome in use and is probably best replaced.