A lot of people here on BITOG top off their oil when the level is still in the safe area. Doing this will not make a bit of difference, except maybe in a few scenarios such as extreme stress, or if you're headed out on a long road trip during which the service interval will pass, or obviously if you have an oil burner. Maybe another scenario I can't think of right now. In these situations, topping off with fresh oil is a good idea, even if the level is above the add mark. Otherwise, topping off the oil when the level is still OK is completely unnecessary. But many of us still do it... it is an OCD thing that makes the owner/driver feel warm & fuzzy, so there is some reward I guess. Besides, I'm not sure this website would exist without such OCD. I've run my current Tacoma for a full 7,000-mile interval with the oil level barely above the add mark. Guess what? Zero issues. But I was only comfortable doing this because it does not consume any oil, it's not in severe service, plus it's a 4-cylinder with a 5.5-quart sump... it could probably go well below the add mark with no issues.