One of our principles is that we should adapt to how you want to work, not vice versa. This is why we allow you to use any email address to sign in to your Microsoft account. We've also heard from you that over time things change with your account -- you might get married, start a new job, move or any number of life events that make you want to change your email address. We want to make it easier to keep your account up to date as these life events happen.