To be or not to be in using INIT or NOINIT in backups
One of my Dev. DBA asked me this question about whether we need to use NOINIT or INIT for a differential backup schedule.
Think about availability option in this case, you can overwrite the existing differential backup using INIT clause but when it comes to restore the combination of Full, Differential or set of Transaction log backups are import. So Restoring a database using a combination of Full, differential, and transaction log backups is a viable solution.
You only need the most current full and differential backup files and all transaction log backups created since the most current differential backup to restore a database to the most current state possible based on this files.
For complete understanding of NOINIT or INIT clauses in BACKUP statement refer to the Books online.