A thorough technical assessment is mandatory. Buyers should prioritize engine health checks, looking for signs of blow-by or unusual exhaust smoke. Inspect the hydraulic system for leaks, cylinder scoring, and cycle time efficiency. For tracked machines like excavators, evaluate the undercarriage wear percentage (links, rollers, and idlers), as this can represent up to 50% of maintenance costs. Always request S·O·S (Scheduled Oil Sampling) reports to detect internal component wear through metal particle analysis.