blade can be sharpened. Many times a clipper blade for dogs is used till it becomes dull, then is thrown out.
Clipper blades become dull when dirt, grit and dander get in between the cutting surfaces of the blade. The first thing that can be done to ensure a long lasting sharp blade is to make sure that the hair or fur is clean. This can be challenging especially in animals with heavy undercoats. The undercoat will trap dirt and sand. It is important to get as much of that out as possible. The second thing that can be done is oil your blade. Most people do not oil nearly enough if at all. As a rule, for every fifteen minutes of clipping time you need to oil. These two things will dramatically increase how long your blade stays sharp.