It is difficult to asses the lifespan of the blade as it is largely determined by the following conditions:
Frequency of use
Overall line length for jobs performed
Intricacy of patterns (where the blade may turn corners more often)
Material type being cut
That being said, a general estimate for lifespan is about six months. As the above conditions will affect the blade, this is just an estimate and could, in some cases, be as low as a few weeks to a month or upwards of one year.
Our Premium Blade is made of a Tunsgten Alloy that may extend the blade's lifespan up to three times the life of the standard Blade, under normal cutting conditions. However, please note that the Premium Blade is not designed to cut materials that fall outside of the range of the regular blade. Attempts to cut denser material types will wear down the blade more quickly. Premium blades can be found here, https://www.silhouetteamerica.com/shop/blades-and-mats/SILH-BLADE-PREM
With any blade, attempts to cut certain materials the Silhouette may not be designed to cut that are more dense may ruin the blade or result in the blade dulling extremely fast. Additionally, certain papers with bits or particles of foreign objects may immediately impair the blade. We strongly recommend against cutting materials with additional foreign objects embedded into them which may harm the blade.
Replacement blades are available for purchase as shown at http://www.silhouetteamerica.com/shop/tools-and-accessories/blades-and-mats.