From the previous slides, the engineer can see that with a WAF of eight, one can easily reach the 5-year usable life requirement. How much WAF can the application have before one no longer meets the 5-year requirement? Using the TBW target of 915 GB that was previously calculated, one can estimate the maximum WAF that the application can produce while still meeting the overall 5-year life requirement. This can be done by using the estimated TBW, known device endurance, and capacity in the equation, and solving for WAF. In this example, the engineer determined that the product may reach five years of life provided the WAF is no higher than thirteen. That seems reasonable given that typical WAF is much lower.