Re: iTunes Help
You set your iTunes up on your computer by logging in with your Apple ID. You cannot switch between different Apple IDs continuously. Apple allows you to switch from the original Apple ID once for "free". After that, you are limited to changing that Apple ID associated with that computer only once every 90 days. According to the message, you have 75 more days to go before you can switch Apple IDs again. This is done primarily to prevent piracy - that is, playing "round robin rename" with your iTunes install on your computer.
Originally Posted by JeevesVic