Often, replacing one or two parts with the most stress will greatly increase the lifetime of the product or even eliminate its planned obsolescence; although this is unlikely in the case of disposable products due to their high ratio of low quality materials.
Often, replacing the one or two parts with the most stress will double, triple, or more the lifetime of the product. You may even eliminate its planned obsolescence, although this is unlikely in the case of disposable products due to their high ratio of low quality materials.