5.3.2 Tracking TODO state changes

You might want to automatically keep track of when a state change occurred and maybe take a note about this change. You can either record just a timestamp, or a time-stamped note. These records are inserted after the headline as an itemized list, newest first⁴³. When taking a lot of notes, you might want to get the notes out of the way into a drawer (see Drawers). Customize the variable org-log-into-drawer to get this behavior—the recommended drawer for this is called ‘LOGBOOK’⁴⁴. You can also overrule the setting of this variable for a subtree by setting a ‘LOG_INTO_DRAWER’ property.

Since it is normally too much to record a note for every state, Org mode expects configuration on a per-keyword basis for this. This is achieved by adding special markers ‘!’ (for a timestamp) or ‘@’ (for a note with timestamp) in parentheses after each keyword. For example, with the setting

(setq org-todo-keywords
      '((sequence "TODO(t)" "WAIT(w@/!)" "|" "DONE(d!)" "CANCELED(c@)")))

To record a timestamp without a note for TODO keywords configured with ‘@’, just type C-c C-c to enter a blank note when prompted.

You not only define global TODO keywords and fast access keys, but also request that a time is recorded when the entry is set to ‘DONE’, and that a note is recorded when switching to ‘WAIT’ or ‘CANCELED’⁴⁵. The setting for ‘WAIT’ is even more special: the ‘!’ after the slash means that in addition to the note taken when entering the state, a timestamp should be recorded when leaving the ‘WAIT’ state, if and only if the target state does not configure logging for entering it. So it has no effect when switching from ‘WAIT’ to ‘DONE’, because ‘DONE’ is configured to record a timestamp only. But when switching from ‘WAIT’ back to ‘TODO’, the ‘/!’ in the ‘WAIT’ setting now triggers a timestamp even though ‘TODO’ has no logging configured.

You can use the exact same syntax for setting logging preferences local to a buffer:

#+TODO: TODO(t) WAIT(w@/!) | DONE(d!) CANCELED(c@)

In order to define logging settings that are local to a subtree or a single item, define a ‘LOGGING’ property in this entry. Any non-empty ‘LOGGING’ property resets all logging settings to nil. You may then turn on logging for this specific tree using ‘STARTUP’ keywords like ‘lognotedone’ or ‘logrepeat’, as well as adding state specific settings like ‘TODO(!)’. For example:

* TODO Log each state with only a time
  :PROPERTIES:
  :LOGGING: TODO(!) WAIT(!) DONE(!) CANCELED(!)
  :END:
* TODO Only log when switching to WAIT, and when repeating
  :PROPERTIES:
  :LOGGING: WAIT(@) logrepeat
  :END:
* TODO No logging at all
  :PROPERTIES:
  :LOGGING: nil
  :END: