Here is a simple explanation of different types of backup methods. Below diagrams are showing three days backup in different methods. The blue color indicated the previous day’s full backup. Green is the growing data of each day. Orange is the quantity of backup data.
I would like to explain one more scenario. One company with a backup policy as follows. Full backups on every month end, Differential backups on every week end, and incremental backups on every day. If they want to restore the data on a week day then they have to restore the Month end backup (Full ) + Last week ends ( Differential ) + Each backup of previous weekdays (incremental )
A complete backup of everything you want to backup. A daily
A backup from last Full Backup to till date
A backup from last backup (Either full or differential backup) to till date