PLOD is a tool designed to help administrators (and others) keep track
of their daily activities.  Since your management will typically have
no idea what you are doing to justify such an exorbitant salary (any
amount of money they may be paying you being classified as
"exorbitant"), and since most people forget what they do themselves,
it's good to keep a record.  Trot your logs out around performance
review time, and show them to your management (after suitable
sanitization) on a regular basis.