The user may need to know exactly what they've just done, so they can undo their work or backtrack. The user may want a high-level overview of what they've done, to gain understanding that they wouldn't get just from memory.
Audit logs are sometimes necessary, such as with legal regulatory requirements.
Highly interactive artifacts may generate huge amounts of recordable detail. Describing certain actions in a human-readable way is difficult. Keep track of enough detail to make the actions repeatable, scriptable, or even undoable, if possible. If the artifact is capable of saving its state, as with Remembered State , give the user the option of saving the history from session to session. It may not be necessary to record every single transaction.