What’s the difference among the sleeve, hydraulic and ball bearing fan?

The warranty for ball bearing fan is 50,000 hours, hydraulic bearing 3,0000 hours and sleeve bearing 20,000 hours. Ball bearing has 5 years life time, sleeve bearing has 2 years life time. Ball bearing fan noise level won’t change for long time, But sleeve bearing fan noise level will grow as time goes. Sleeve bearing is cheaper than ball bearing fans. get price