Do it before further transfers or a petition deadline make the route harder to verify. The main preparation dependency may be obtaining older statements, not the time required to send the final wire.
Sequence requests around missing links
Request unavailable bank records early and track the institution responsible for each response. Do not manufacture a simplified path when an intermediary is difficult to document. Resolve gaps with counsel and preserve the real chronology.
Completing the transfer file improves filing readiness, but adjudication, visa availability and family processing remain separate timing questions. Start with the item that has an external clock. Bank retention policies, an employer’s willingness to confirm historical earnings, a company’s access to old accounting systems and a relative’s availability to sign a declaration all get harder rather than easier with time.
List them first and begin the requests before assembling anything you control yourself. Track each request with the date it was made and the person responsible for answering it, because chasing an institution is usually a matter of persistence rather than escalation. Build the chronology while memories and correspondence are still accessible, then verify it against the documents as they arrive rather than the reverse.
Completing the financial record improves readiness to file; it does not determine adjudication times, visa availability or the separate steps that follow for family members.