I put a small drop of lube on the fingers I handle cases with, so that a tiny amount is transferred as I feed the press. It smooths up the press stroke a lot without the hassle and mess of fully lubing cases. One variation that also works, is to lube every 5th to 10th, with similar results. In this case, though, you might want to clean the brass afterwards. The finger method doesn't leave enough lube residue to matter.

It is not necessary, as carbide dies are made to not require lube, but it helps slick up the whole process. Give it a try and see of it helps...it certainly won't hurt the dies or cases.

That's an idea that never crossed my mind, lubing cases for sizing in a carbide die, unless I'm using bottle necked rifle carbide die in a progressive press. If I had tolube the cases for use in a carbide die why would I spend the extra money for the carbide die?
I made the switch to all Redding carbide dies a number of years ago, so this a non issue as far as my reloading experience goes.
Jim

No needed for straight walled pistol cases, just make sure they are clean. Any bottle necked, or taper walled case should be lubed.
JCN