Micro Cooling Fan bearing selection

"Micro Cooling Fan" bearing up choice because bearings are divided into two kinds of ball bearings and bearing oil. Ball bearing long life, low noise, but the price is very expensive requirements. Oil-bearing ball bearing service life is shorter than 1/3, may be some noise (over one year) in use for some time, but the price is cheap. After more understanding since we can choose, but if any ball fan and oil prices "Micro Cooling Fan" almost the price, it indicates that it is the old ball bearing products do not buy or eliminated. And each of the new "Micro Cooling Fan" push manufacturers in the bearing life (except clear that the oil-bearing outer) ball bearing are not exceeded, and there will be noise in the future use.