Final answer:
Voice mails should be returned within 24 hours to adhere to professional etiquette. For calls or videoconferences, like the one Sylvia Varela requested, it's important to follow through with promised communications and respond promptly.
Step-by-step explanation:
When considering professional etiquette, voice mails should be returned as promptly as possible, ideally within 24 hours to show respect for the sender's time and to maintain good communication. While professional etiquette may vary slightly by industry, a prompt response is always appreciated.
When setting appointments for calls or video conferences, as mentioned in an example request by Sylvia Varela, it is good practice to offer a specific time frame for the call, like '15 minutes within the next week', and to follow up phone calls regarding important matters, such as checking the status of an application, if you have indicated that you will do so.
In scenarios where timely communication is essential, such as with interstellar communication proposed in the hypothetical example about receiving a message from a civilization 35 light-years away, responses could take much longer due to the vast distances involved. However, the principle remains the same: clear intentions and stick to agreed-upon timelines for responses.