Final answer:
The standard homeowner's policy usually covers only 10% of the personal property limit of the primary residence for other residences such as a rented beach house.
Step-by-step explanation:
Rodney, the insurance agent, suggests that Ralph and Sybil consider increasing the limit on personal property at the beach house. This is because the standard homeowner's policy typically provides a limit of only 10% of the personal property limit on their primary residence for personal property at other residences. Therefore, it is important for them to review their current coverage and assess if they have enough insurance for their belongings at the beach house.