When should I restore the model, msdb and distribution databases?
You should restore the ‘model’ database, if you have changed the database template of your MS SQL Server. You need to restore the ‘msdb’ database, if you have changed the scheduling information or you want to restore the backup and restore history of your databases. If you are running the replication components of MS SQL Server, then restore your ‘distribution’ database.
Restore the model database if you have changed the database template of your MS SQL Server. Restore the msdb database if you have changed the scheduling information or want to restore the backup and restore history of your databases. If you are running the replication components of MS SQL Server, then restore your distribution database. You need not restore these databases if you just want to restore a user database. For more information on Microsoft SQL Server model, msdb and distribution database, click http://www.microsoft.com/sql/.