Normally the firms maintain one ledger for all the accounts involved. So long as the volume of transactions is small and the number of accounts is limited, this works fairly well. But, as the business expands and the number of accounts increases, especially those of the debtors and creditors, maintaining all accounts in a single ledger becomes impractical. The ledger becomes too bulky and location of errors involves more time. Hence many firms decide to introduce multiple ledger system whereby separate ledgers are kept for debtors and creditors and the entries are recorded in each ledger in such a way that a separate Trial Balance can be prepared for each ledger. This is called 'Self-balancing System'.