After each adventure, it is highly advisable that one or more members of the party update the Adventure Log with a recap of the session.
The reasons are not only for the edification of posterity. As all of the players may not be present for every session, the adventure log simulates sharing information, gloating and bragging back in town in-between sessions. Also, information and clues may appear, separated by many sessions, and possibly even from different DMs. So, ignore the usefulness of the Adventure Log at your own peril.
Additionally, players who post an Adventure Log within 48 hours of a run may add 100 xp to their character. If this post is done in character and includes roleplaying (as opposed to a straight recounting of events), an additional 50 xp can be added for a total of 150 xp.