For departures, I can always keep just to the side of it fairly well. (IRL, you’ll run over the centerline lights and make a horrible noise in the cockpit if you put the wheels directly on it).
On arrivals, it depends on many factors such as the ILS alignment, winds, visibility, whether I’m using APPR or not.
The centerline isn’t an absolute, you don’t have to be as close as possible to it. It’s a strong reference for not ditching it in the grass, especially on larger aircraft.
For real pilots? They have many hundred of hours spent practicing, even more so if they are type rated for that aircraft. And with more sophisticated autopilot/autoland features on modern aircraft, it’s quite rare (barring and emergency) to see an aircraft at least not come close to centerline.