Keep a current database dump of the model database.
Each time you make a change to the model database, make a new backup. If
model is damaged and you do not have a backup, you must reenter all the
changes you have made to restore model.
Truncate the model Database’s Transaction Log
model, like master, stores its transaction log on the same database devices as the data. Always use dump database to back up the model database and dump transaction with truncate_only to purge the transaction log after each database dump.