I'm just curious how did you check that Dimitri is making a daily full backups?
I have 5 years retentions for my full backups, but they are full monthly backups. For daily and weekly backups, we use incremental and differential types.
Well. Let's imagine I backup a single file every day. Every day this file is changing its contents, so what backup level I should use for it (I assume I do not use bacula delta plugin)? You could ask what single file, I can respond a virtual machine disk image. :)