I have found that a lot of people have asked this question: Why did Apple force me to reset my Apple ID password?

Fact is - I myself went through that question recently when my iPhone showed me a notification saying I need to change my password and forced me to reset my password. Even on Apple’s community pages, there were no answers to this.

So I decided to call Apple Support and this is what they have told me: If you have not changed your password for more than 2 years, you will be forced to reset the password! There you have it - this is one of the reasons why Apple would force you to change your password. It is recommended to keep changing your password from time to time (about once a year should not hurt) or you might to reset your password sitting in traffic, waiting for a red signal to turn green; well, who knows?