Do not assume the dispute is resolved by what either driver says at the scene. Photos, video, witness accounts, vehicle damage, reports, and other evidence may help reconstruct what happened. Fault rules vary by state.
Uninsured or underinsured motorist coverage, other policies, or additional responsible parties may matter. The coverage analysis should be based on the actual policies and circumstances.
Deadlines vary by state, claim type, defendant, and sometimes the involvement of a government entity. Waiting can also make evidence harder to preserve, so timing should be evaluated early.