Avamar Backup retention

I have this backup policy:

• Daily full backups shall be kept for 35 days on the Backup System.
• Weekly full backups shall be kept for One (1) Month on the Backup System.
• Monthly full backups shall be kept for One (1) Year on the Backup System.
• Yearly full backups shall be kept for Three (3) Years on the Backup System

I just want to confirm if I'm protected forever.  unless someone deleted some files? 

Do I need a full backup yearly for an extended period or infinite?  to have full protection 

Snapshots for 3 months?  the interval between snapshots if something deleted will be lost? right?