The core tasks related to the maintenance of a SQL Server database are backing up the database and log (including shipping the logs to a standby server), rebuilding indexes, updating statistics, and running integrity checks against the database. These are the ongoing repetitive tasks, which are best run on a scheduled basis and are the backbone of the maintenance plan. Other tasks related to maintenance involve managing access by the users, maintaining data files, and monitoring performance. These tasks are more apt to be performed on an ad hoc basis when the need arises.