From www.dbalawyers.com.au: The ATO requires that Section 104A trustee declarations must be retained for the life of the SMSF or at least for 10 years after the SMSF winds up.

There is conflicting guidance regarding the retention period, with some materials suggesting declarations be kept longer than 10 years even for trustees appointed after 2007.

If a trustee declaration is lost, auditors should file an auditor contravention report, but only once.