We use two steps: 1. Insert a medical-grade endoscope through the spark plug hole to visually inspect cylinder wall scratches and carbon buildup on the piston top; 2. Extract an engine oil sample to check for large metal debris or emulsification (caused by coolant leakage).

Many car owners do not have their first maintenance done at authorized dealerships, leading to gaps in early data. In such cases, we do not blindly trust the odometer; instead, we analyze the tire production dates and wear levels, as well as the depth of grooves on the brake disc edges, using the "gold standard" of physical wear to infer the intensity of early use.

If insurance claims records are accessed, there will usually be notes like "the insured vehicle is fully responsible for hitting a fixed object" or "third-party liability insurance payment." We can roughly reconstruct the accident scene based on this and cross-verify the stress points on the vehicle's frame with paint thickness gauge data.