Audit evidence must be drawn from that audit's observation period, the period of time directly before the audit that the auditor examines to determine if your controls are in place. By definition, these periods will be different for past and future audits.
Additionally, although some multi-stage audits may seem to be asking for the same evidence again, that is rarely the case. For example, the SOC 2 Type 1 assessment only observes the design and implementation of your controls, while the SOC 2 Type 2 assessment also observes the effectiveness of your controls. This requires significantly more detailed evidence.
Even pieces of evidence that may seem to be identical, such as your existing policy documents or cybersecurity configurations, must be re-reviewed before every new audit. If these items have changed since your last audit, submitting outdated evidence may result in exceptions or time-consuming resubmissions.