Why auditors require enterprises to provide documents and data of the previous years?

My new audit firm requires me to provide documents and data of the previous years which were already audited by other auditors. Why? 

There are the two reasons as below: 

1. Some transactions are recorded in the current year with values depending on the balances at the end of the previous period (For example: The cost of goods sold of this year may partly depend on the inventory balances recorded at the end of the previous period).  
2. The figures presented on the balance sheet of the current year can be accumulated from transactions that occurred in previous years (For example: fixed assets purchased from previous years). 

According to the guidelines of the standard (VSA 510 Initial engagements - opening balances), the auditor may review the audit records of the predecessor auditor to obtain relevant and reliable evidence. However, if this is ineffective (for many reasons), the auditor has the right to request the enterprise to provide data and documents of transactions arising from previous years for the implementation of appropriate audit procedures. Each auditor is solely responsible for their own opinion, so they are not compulsorily required to use the results of another auditor's audit.