I could be wrong, but I seem to remember from an update course that unlike the stimulus payments, the advance child tax credit will have to be paid back if 2021 income is not what the IRS calculated the credit on. This year I had a few clients who could not come up with how much stimulus they got, but when I looked at their 2020 income and realized they were not going to get any more anyway, I just plugged in the standard amounts or entered zeros. (Say they really got $1k instead of $1200, but their 2020 income was too high to get anything, it made no difference what I put in there because they were definitely not going to get a recovery credit.) We won't be able to do that with the advance child tax credit in 2021 and will have many clients moaning when we present their tax bill. Right now we don't know enough about it to warn them. The IRS may do that, but how many people won't read it because they are thrilled by the thought of getting extra income?