From an audit and governance point of view it depends on what you are recording, the jurisdiction and the record keeping requirements.
In the UK the Data Protection act lays requirements on the veracity of records specifically that they must be correct at all times and where they are not there are timescales upon which they must be brought into a state of accuracy. There are also requirements around consent to maintain the records, specifically if the person that the record relates to asks for them to be deleted and you don't actually delete them.
Depending on how rigorous your audit logging is then you could delete everything immediately with the audit log as your backup.
From a systems point that of view it is better to be able to undo 'mistakes' but this can produce legal impacts. Google Oliver North email PROFS.
