There is something about finding rings that changes a person. Now, most people come back from these adventures in our world, but Gandalf's warning holds true--they are never the same.
For some, the ring they receive is a wedding ring, given by their spouse at the altar. It is an outward sign of the inward change. That new husband or wife has accepted their vocation (from the Latin for "being called"). They have not just changed their jewelry but their soul, their state in life. From then on, there will be challenges as well as joys, but their direction is set.
Nuns may wear a ring as a sign of their commitment as well, as a sign of their consecration and new state of life. Each of them has set off, as well, on a new adventure, taken the first step in a particular direction.
Bishops wear rings, the most well-known being the Ring of the Fisherman, worn by the Bishop of Rome (the Pope). These episcopal rings are signs of their authority, and they are, too, signs of their vocation--of their being called to be priests and, then, to serve as successors to the apostles. Again, there are particular challenges as well as joys, but that direction is set.
Once you have the ring, the adventure begins. Each of us the bears one carries a joyful burden--a light yoke--that is our particular calling. And while callings may be the same--many are called to be married, or consecrated religious, or priests, or bishops--the individual adventure is different. When we put on our ring for the first time, none of us may know what lays ahead on the road, or even which road we will be taking. What we know is who with, and who for.
The Road goes ever on and on
Out from the door where it began.
Now far ahead the Road has gone,
Let others follow it who can!
Let them a journey new begin,
But I at last with weary feet
Will turn towards the lighted inn,
My evening-rest and sleep to meet
- The Return of the King, Book VI, Chapter 6