This bill modifies how the Department of Veterans Affairs handles evidence in veterans' disability benefit claims at different stages of the appeals process. For supplemental claims filed within one year of an initial decision, the VA must reconsider all evidence on record. For supplemental claims filed more than one year after the initial decision or after appeals to higher levels, the VA must consider both the original evidence and any new relevant evidence presented. The bill also restricts evidence in cases sent back by the Court of Appeals for Veterans Claims, limiting the Board of Veterans' Appeals to previously considered evidence unless the veteran submits new evidence within 90 days of remand. The VA must issue regulations implementing these changes within 180 days of enactment, and the rules apply retroactively to supplemental claims filed since August 23, 2017.