I always add 5qts & that gets me within a few mm of the max line. If I am doing mostly highway driving, then I only need to add a quart every 4000-5000 miles (I run 15W-50 full synth, change oil every 10k, filter at 5k). City driving / short trips, I have found that I lose a quart every 1500-2000 miles lol.