Branch accounts
A business with multiple branches may keep a separate branch account for each one, tracking goods sent to the branch, sales made there, and expenses incurred, to assess each branch's individual performance -- useful for deciding which branches are thriving and which may need attention or closure.
Control accounts
A control account is a summary account that totals the balances of many individual accounts of the same type, providing a quick cross-check on the ledger without needing to add up hundreds or thousands of individual balances by hand. The sales ledger control account summarizes all individual customer (debtor) balances; the purchases ledger control account summarizes all individual supplier (creditor) balances.
Example 1: A business has 200 individual customer accounts in its sales ledger. Explain why a sales ledger control account is useful here.
Rather than manually adding up all 200 individual customer balances every time a check is needed, the sales ledger control account keeps a running total of all sales, receipts, and adjustments affecting debtors as a whole. If this control account total doesn't match the sum of the 200 individual balances, it signals an error somewhere in the sales ledger that needs investigating -- a much faster check than manually re-totaling everything each time.