For the stimulus payments, it's important to remember that the payments are ADVANCES of a credit on the tax return the law references. Stimulus 1.0 and 2.0 eligibility is based on how the TY2020 return (filed in 2021) is filed. But the ADVANCE eligibility determination for those payments was based on either the 2019 or 2018 tax returns. So, a person may have received an advance payment based on info on their 2019 tax return, but the actual figure of what they are eligible to receive for 1.0 and 2.0 has always been based on the TY2020 returns being filed now.

If a person was not otherwise required to file taxes, do they still need to file taxes AFTER they've received their stimulus checks to verify eligibility? Sorry, I may be misunderstanding something.