Final answer:
An accounting issues memo is necessary for judgmental transactions and highly material transactions.
Step-by-step explanation:
An accounting issues memo is necessary for judgmental transactions and highly material transactions. In these cases, the memo helps to document the rationale behind the accounting treatment chosen and provides a record for future reference. Simple transactions, on the other hand, may not require an accounting issues memo as the treatment is straightforward and does not involve significant judgment or materiality.