Do new hubs need to be adjusted prior to use Do new hubs usually come adjusted, or one needs to adjust them prior to use. I have a new Shimano Claris hub, and it does not seem to be as smooth rolling as my previous Tiagra hub. Should I try to adjust it, or leave it as is?
Most lower end hubs do not come perfectly adjusted from the factory.  A quality LBS will have a step in a bike build process that checks and/or adjusts the hubs accordingly.  It can be hard to adjust a hub that is unbuilt and between that and machine assembly, they are often close, but not as good as they can be.  

If you are feeling vibration, I would guess they are too loose and look into adjusting them as soon as possible to prevent damage.