Sorry - I should have given more info.  3 children.  Oldest lives with Mom (my client) for most if not all of the time, so I'm using 12 months, and he was 17 in 2024.  Younger 2 are 6 months (yes 6/6 when I asked Mom) with each parent, and divorce agreement says the younger 2 are on Dad's 2024 return.  Mom qualifies for HoH with at least the oldest child, and he's too old for the child tax credit in 2024.  She doesn't qualify for the EIC because of income.  I'm assuming she doesn't get the child credit for younger 2 since she's not claiming them as dependents in 2024.  So I don't think it matters - but - I'm thinking I add 2 younger children with code Q?

And would your answer be different if Mom says "well actually younger 2 actually lived with me for 7 months if you carefully count the nights - or 9 or whatever".

I don't think it will matter on the numbers if I leave 2 younger off of the returns because she's already got the HoH covered, but oldest is 18 in 2025 so it may matter going forward.  So I'm wondering if this falls into "it's a good idea" category.

Thanks for your time!