One of the main advantages of the basic saw tooth chain is that it can be resharpened with a round file.
An exception to this rule are STIHL carbide-tipped chains which are called "Duro chains". They are particularly wear resistant and their extremely hard cutting edges have to be resharpened with special diamond cutting wheels. Please contact your STIHL Approved Dealer for more information.
All other saw chains can be resharpened relatively easily with the right tools and technique.