For this used 2023 WEY Blue Mountain PHEV—one of the reliable used hybrid cars on the market—with 31,000 km mileage, routine maintenance covers both the 1.5T engine and electric components. Engine services like oil and filter replacements cost around $150-$200 per session, similar to gasoline vehicles, keeping maintenance cost manageable for owners. The high-voltage battery typically comes with an 8-year/150,000 km factory warranty, covering major battery issues if within the period, which helps preserve used car values over time. Annual maintenance costs average $500-$700, including inspections of brakes, suspension, and hybrid system sensors. Proper charging habits (avoiding frequent deep discharges) help extend battery lifespan, ensuring the vehicle remains a worthwhile investment for those who buy used cars.