Mazda: miata wheel hub assembly, spindle nut, wheel bearings

Question
I have an '01 miata, one of the front bearings is going out, should I replace both of them or just bad one?? How do you go about replacing them if I wanted to do it myself?

Answer
Wheel bearings are not common, replace only what is affected.  Most fail due to an impact to a wheel or driving through deep water.  Either way the issue takes a while to manifest itself.

The hub assembly is available from Mazda and should be replaced as such.  Removal of the brake caliper as an assembly is required.  The spindle nut uses an indent keeper so this will have to be expanded out so as to remove the hub.  Be sure to re-indent after torquing the spindle nut.  Fairly simple job.