Ask HN: Implementation of Account Ledgers

It seems to me that the mechanism to maintain a ledger of user accounts is mostly the same across companies and domains, even though it is probably implemented from scratch in each company. Even if the account asset type is different, the concept of transfers (credit one account, debit another), account creation/update, history, statement generation, and correctness of calculations is mostly the same for an e-commerce store or an exchange.

Has this been true in your experience?