The only thing I did not like about casting Elijah Wood (and don’t get me wrong I love him as Frodo) is that he was a bit too young for the role. Frodo is supposed to be in his fifties when he sets out from the Shire. Sam and Merry are about the same age but are more than 10 years younger than Frodo. In age Martin Freeman would have been better but by temperament Elijah was the better Frodo. Bilbo is more of a “fuck it, let’s do this” kind of guy whereas Frodo is much more deliberate and cautious. Martin Freeman was also an amazing choice for Bilbo.
During the 15 or so years when technically Frodo possessed the ring he never used it. The first time he put it on was in Bree. I doubt he was much affected by it during those years.
As time went on, people began to notice that Frodo also showed signs of good 'preservation': outwardly he retained the appearance of a robust and energetic hobbit just out of his tweens. 'Some folk have all the luck,' they said; but it was not until Frodo approached the usually more sober age of fifty that they began to think it queer.