Normal Bearing Wear
Big Size Air End (Bigger bearings) versus Small Size Air End ( much smaller bearing is used).
This one determinant factors on the Price of Compressors.
Low speed (1500 RPM) screw and High speed (9800 RPM) screw that produce the same air delivery.
The big and low RPM screw will have a much longer bearings change intervals.
1. Thrust Bearing Load
2. Temperature Change
3. Design Challenges