In the wild
Unlike timing tests that use the Date object, the Navigation Timing API can be used in ways that do not affect page load. This makes it extremely useful for measuring page load latency in the 'real world', as experienced by actual users—rather than as tested by a developer using a development computer inside a corporate network.

For example, XHR can be used to pass performance.timing data to the host server every time a page is loaded (or unloaded). This produces statistics in real time, but isn't very efficient. Alternatively, timing data could be recorded in local storage for a subset of users for a subset of pages, and periodically packaged and filed to the server. In this way, the API provides a simple way to build up historical data for page performance.