The final type of life evaluation is L10 life. L10 life is defined as the number of hours that 90% of a group of products can be expected complete or exceed without failure. This method of evaluation is much more accurate for determining the life of a fan because it directly measures the expected life of the bearings. So why focus so much on the life of the bearing? This is because the most common failure mode of a fan will be the bearing as it is the primary moving component within an assembly. While L10 life is purely defined as a measurement of the bearings, Sanyo Denki uses an internal L10 life model which more accurately defines a life taking into account real world conditions. All Sanyo Denki products use the L10 life method to define product life.