The length of usability varies from person to person, since it is tied to how much the blade is used. Buyers that go through a lot of blades per week are usually on intense projects where the blade sees daily use. You can also be unlucky enough to get dull blades directly from the manufacturer, something that isn’t too uncommon with bulk products. When used for the first time, test the blade out and make sure that it is as sharp as the brand claims. This test will keep you from having to play a guessing game on the quality of new blades that you need to use immediately.