My sister puts regular oil changes at 6,000. Should that be fine versus synthetic?
If she uses regular oil, I’d change it every 4,000 or 5,000 if I were her. You can change your oil every 6-8,000 with synthetic, but I wouldn’t change regular every 6,000. If you do a lot of driving, I’d change regular every 4-5,000 or change it every 6 months if she doesn’t drive much.