Honda recommends 0W-20 engine oil for its vehicles, including the Civic, primarily to meet fuel economy standards. While some believe 5W-20 could suffice, especially in moderate climates, using 0W-20 is advised for optimal performance and warranty compliance. The higher cost of 0W-20 is attributed to the superior quality of its base stocks. It's also emphasized that modern vehicles do not require oil changes every 3 months or 3,000 miles, contrary to outdated recommendations. Adhering to the manufacturer's guidelines ensures better engine health and longevity.