We have a request from SoX auditors to keep the backup session in Internal Database > Sessions for one year in order to prove that the backups are completed without any error.
We change all the tapes weekly and we have a cycle of 3 set which means every 3 weeks the tapes are reused. To be able to re-use them we set on every backup specification protection on 13 days to be expired when we re-use the tapes.
With this settings we have the backup sessions only for 2 weeks.