Our midsole alone has a minimum life expectancy of 3 years. The life expectancy of other components of Klas & Sylph’s footwear, on the other hand, depends on individual product usage, conditions of use, and characteristic wear patterns of the user. In fact, usage duration (i.e. number of days from the date of first use) can hardly be used as an accurate measure of life expectancy of a product since usage duration alone cannot determine if the product has undergone heavy usage or not. In any case, we recommend you to consider replacing your existing pair of Klas & Sylph when its outsole pattern becomes significantly abraded.