I check the oil in our cars after they've sat, typically overnight, and haven't been running for 8+ hours. If I have reason to worry that an engine might be low on oil and I can't wait that long, I'll check it and read it and as long as I get a fairly clean 'line' on the dipstick and no smearing all over the rest of it, if there's oil on the dipstick and at or above the 'low' marking, I call it good. Letting it drain longer will simply show it closer to the middle.The thing us that different people wait different time for the oil to drain. Usually, people who overfill are those who don't wait enough.