I have, I think, three or more Apple IDs, with two being the main ones. It is a huge pain and I wish Apple would allow merging them. I wound up with them when Apple wouldn’t let me use existing ones. For one thing, I was one of the unfortunates who had iTunes and then got the MobileMe service, which required two IDs. In particular it is often confusing which Apple ID to use. Their system really doesn’t seem set up for multiple IDs even though they’ve required them in the past.
If I start using the “Two-Factor Authentication”, is it going to cause a problem with the multiple IDs?
I ended up with multiple Apple IDs. So I contacted AppleCare by phone, and they helped me out. So now I only have one Apple ID.
I’d contact AppleCare and discuss it with them.
I mistakenly turned on Two-Factor Authentication, and turned it off, because it was such an inconvenience to use. I’m all for security, but I found it too cumbersome. I guess if I was using it for purely business situations I’d use it, but for my everyday personal use for devices in my home I didn’t feel it was necessary.