The problem is that there are no happy answers when something has to be lubricated whilst exposed to dirt. Oil or grease traps the gritty dirt and forms a substance almost identical to valve grinding paste, so the metal gets worn away. On the other hand if you don't lubricate it the two dry metal surfaces can adhere to each other and tear ("spalling"). The proper answer is to use compatible metals and/or seal the joint so that no dirt can penetrate, and lubricant can be retained.
The answer usually is to try to do a bit of each. In particular, do not have mild steel rubbing against mild steel, or even worse, aluminium rubbing against aluminium. Mild steel against hardened steel is fairly good (it's wheelbarrow engineering, but good quality wheelbarrow engineering). Hardened steel against bronze is quite nice, and you can make it better by making the bronze part porous and soaking it in lubricant during manufacture. For those Greenfield front suspension joints, a good solution would be to use hardened steel pivots/pins (that is, high tensile bolts instead of soft bolts), a bronze bush in the center axle pivot bearing, and bronze washers rather than mild steel ones in all three front axle joints, then wipe grease sparingly on all of the parts regularly. Finally, don't work in dirty conditions that would get grit in the bearings, and wipe it off if it occasionally happens.
But having said all that, it is almost always best to follow the manufacturer's recommendations (not the local dealer's recommendations, unless they are the same).
