oil change interval on 1990 Mazda RX-7

How often should the oil be changed?

Asked by for the 1990 Mazda RX-7
2 answers
3-5K for conventional oil. Up to 8K for premium synthetics. Pull the dipstick and if th eoil is darker then a good Amber Ale then it's time. The dirt on the oil gradually destroys the bearings. Happy Holidays.
3000 miles is a good#