[drc500free]

Double entry is helpful when you have a large number of internal accounts that regularly transact with each other. The primary benefit is that you can determine the balance of any given account by just looking at that one account, and the business as a whole by combining all transactions across all accounts.

In an accounting sense, it's useful for implementing accrual bookkeeping. Accrual bookkeeping matches every dollar of revenue with all associated expenses by hiding cashflows in asset and liability accounts, until it's time to match them all up and recognize them simultaneously.

If you're not working with a system where you have a lot of transactions flowing between accounts where you control both ends, you might not get as much benefit from double-entry.