Safe to delete older differential backups?
My external disc drive I use for backup is gradually filling up, it has 2.5 Tb in full+differential backups made for the last 5+ months. Is it safe to delete any of the earlier differential backups since the first full backup on which they are based, to free up space on the external drive? That is, will I be able to restore all my files using the first full backup plus one of the more recent backups?
Note, I am backing up using file backup because I have data files on several different internal hard drives in my computer that I back up and I wasn't able to use other kinds of backup specifying several different disks.