Scene and event records
Depending on the event, useful records may include photographs, video, incident or crash reports, measurements, product information, and the names of witnesses. NHTSA describes scene evidence, vehicle photographs, police reports, and medical records as different parts of a detailed crash investigation.
Identity and responsibility records
Save the names and contact details of the people and organizations involved, relevant insurance information, and any report number. Do not assume that the first named party is the only person or entity that may matter.
Medical and impact records
Treatment records document clinical observations and care. Bills, wage records, receipts, and written work restrictions document different kinds of financial impact. Keep these categories separate so their source is clear.
Records you do not control
Businesses, vehicles, devices, public agencies, and third parties may control relevant records. Retention periods vary. A lawyer can advise whether a preservation request or formal process is appropriate for the facts and jurisdiction.