Is there ever a time when Apple requests a social security number and what would those cases be?

If you get an email with a link that asks you for a social security number it is phishing. See: Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

But the following is valid -- from Identity verification for Apple Card or Apple Cash - Apple Support

The first time that you verify your identity, you might be asked for this information:

• Your full name
• Your social security number
• Your date of birth
• Your home address3
• Answers to questions regarding your personal history
• An image of your driver’s license or state ID card

It is not even required when setting up Apple Pay (I know I did not have to use it when setting up Apple Pay). Apple has no use for your SSN and it would serve them no purpose at all anyway. They would not even have any way to know if any number you gave them really was your SSN or a made up one.

An Apple finance parter (Barclays or Citizen One) May ask for it when or if applying for finance, but that request will originate from the finance partner, not Apple, when the Bank runs your credit check for financing approval.

But since nothing about your AppleID nor any Apple service tied to it has any relationship at all with your SSN, knowing it would be utterly useless to Apple anyway.

So no, Apple will never ask you for your SSN (or in Canada, your SIN).

I think the only time they require that is when setting up Apple Pay. They do not request it for other things. An Apple card requires the last 4 of your social security number.

I delete any such request.

If I am wrong, they can send it to me again with greatly clarity if they really want me to answer the question.

I would much rather be safe rather then sorry.