Form 8867 due diligence applies whenever you claim EITC, the Child Tax Credit or Additional CTC, the American Opportunity Credit, or head-of-household filing status. The penalty is assessed per credit, per return — mistakes compound fast.
Ask the questions, document the answers, and keep the substantiation. Residency records for a qualifying child, school or medical letters, custody documentation, and business records for Schedule C income all belong in the client file.
Contemporaneous notes matter more than memory. A short summary of what you asked and what the client answered, saved in the return, is often what turns an examination into a non-event.
Retain due diligence records for three years from the later of the return's due date or the date it was filed. A cloud office with automatic backups makes this effortless instead of a filing-cabinet problem.