Sam or Frodo

[Nazgûl-king]

Originally Posted by Groin Redbeard

Sam was new to posessing the ring, Frodo had carried it for thirteen months. So Frodo resistance wore down over the months, while Sam only had it for a couple of hours tops.

As for Sam wearing the ring in Mordor, I don't know how Sauron could have missed him.

Yeah, there’s the possibility that he was distracted by the war, but I would think that Sauron would hold finding the ring to be of greater importance. So how did Sauron miss Sam's use of the ring in his own land?