So we all know that ball bearing is better than sleeve bearing... but is it? Sleeve bearing looses its oil faster and starts rubbing and making noise and resistance. But all you need to do is put a drop of oil in it and it's good as new. While ball bearing lasts longer, you cannot oil a ball bearing fan (i think). And a sleeve bearing fan is quieter in the beginning. So all you need to do is oil the fans every once in a while (same time you would clean out the dust) and they will last, while a ball bearing fan cannot be oiled (I think). And also sleeve bearing fans are cheaper. So are ball bearing fans really better? I think sleeve bearing fans would be better as long as you oil it regularly, and that is no problem because you need to clean dust out regularly too.