Put the auto-rx and drive the mileage no matter how long it takes to accumulate the mileage. I have a 68 Firebird that I drive only 100-1500 miles per year. It was an elder ladies car that was driven only locally. Pretty dirty motor over the 30 years of service. I had the initial dose of Auto-Rx in for 8 months before I had accumulated 600 miles. It did a super cleaning job and minimized all oil leaks.My second dose was put in 9 months ago and is still in the motor, I am approaching 1000 miles. I am thrilled with my results. I had replaced valve cover gaskets about a year ago, and what I see now on the top end of the motor is beautiful compared to what it was.