It can be useful to maintain lists of completed next actions, but you need to think about up front what will be helpful to maintain and what won't be worth the effort. As an attorney, I record a lot of my activities into a separate time-keeping/progress note system, so I don't need to separately archive many of my tasks. I certainly don't need an archived list of completed tasks like "return library book." But for completed tasks where it may be important to refer to them to see IF they were completed or WHEN they were completed, then it may be useful to keep track of them. Depending on their level of significance, I may cut and paste completed next actions into my project support materials (the note section of my project list) or I may simply archive the completed next action using the Palm software knowing that I can import the archive if I ever need it (I never have). Also, as part of my weekly review, I look back over the previous week's completed next actions to see if they generate any new thoughts for new next actions or projects. Once this is done, I delete them, archive them or copy them to the project support materials. I think this part of the review is important, so I would at least want to keep completed next actions around long enough to make them part of my weekly review. I still keep a telephone log for my voice mail messages, but for me it operates as an @calls list. I don't need to put it in my Palm because I return all the calls from my office and just keep it on my office computer as a Word document. I note the date and time the call was received and a short summary of the message. Then I note whether I returned the call and the date of the returned call. This has proven helpful to refer to on many occasions.
