You should typically change your oil every 5,000 to 7,500 miles if using conventional oil, and synthetic or semi-synthetic oils can often last 7,500 to 10,000 miles or more between oil changes. However, the ideal interval depends on your vehicle model, oil type, driving conditions, and habits. Key points:

• Follow your vehicle owner's manual for the manufacturer's recommended oil change schedule.
• Modern synthetic oils allow longer intervals than the old 3,000-mile rule.
• Many newer cars have oil-life monitoring systems that calculate optimal oil change timing.
• If you do a lot of short trips or drive in extreme conditions, more frequent oil changes may be needed.
• Even if you don’t reach the mileage, changing oil twice a year is recommended to prevent moisture buildup and degradation in the oil.
• Electric vehicles do not require oil changes.

In summary, consult your owner's manual first, but for many modern gasoline vehicles, oil changes every 7,500 to 10,000 miles or twice a year is adequate for maintaining engine health and performance.