Hello Maria,
Maybe they meant that some data has to be kept for at least 5 years by legal regulations. As far as I know Italy is quite similar to Spain considering the legal regulations, for example in Spain we have to kept 6 years the invoices on the SAP system. This doesn't mean the invoices has to be on the database, you could archive the data if you want. The only limitation is that you have to have available the data in case it is needed due a legal inspection or requirement.
Best regards.
Miguel Angel González