As the name suggests, a post hole digger is primarily used for digging holes to install posts.
Compared to other tools, such as a spade, it is much easier to use when digging holes because it requires much less time and physical effort. The user does not have to constantly bend over to dig.
A spade and similar digging tools are also not ideal for post hole digging, as they will create holes much bigger than is needed due to their shape.
Post holes are usually required to be deep and cylindrical, with even sides, in order to support the bottom of a post when it is in the ground.
Post hole diggers are designed with long handles which means they can dig deep within a hole to depths which would normally be out of the user’s reach.
A post hole digger can be used to dig holes for a number of different outdoor objects, for example: