The Hobbit Topic Tracking: Luck
Luck 1: Just when the dwarves are about to be sat upon by the trolls, Gandalf appears and starts to create strife between the trolls. While he later reveals that he heard from his friend Elrond that trolls were in the area, and that is why he turned around and came back for them, it still doesn't account for the fact that he arrived just in time to prevent their deaths.
Luck 2: The luck in this section is a mixture of good and bad. The travelers just happen to rest in the cave that the goblins use as their main entrance to the outside world. This is terrible luck, but fortunately Bilbo wakes just as the goblins are stealing the ponies, so he has enough time to warn the others. If Bilbo hadn't cried out, Gandalf may have been captured along with the others.
Luck 3: The first thing that Bilbo finds when he wakes from his fall is the ring. Without this ring, the tale might have been very different. When he is playing the riddle game with Gollum, he just happens to yell for time when 'time' is the correct answer to Gollum's question. Because Gollum thinks that Bilbo knows more than he actually does, Bilbo is able to follow the creature through the tunnel and rejoin his friends.
Luck 4: Bilbo ends up on the other side of the mountains, shortening his journey significantly. He also happens to find his friends pretty quickly. When they are all stuck in the trees and it looks as if they are going to die, the eagles appear and they rescue them. They have had no contact with the eagles prior to this. If the eagles had not appeared, they surely would have perished at the whim of the goblins and wargs.
Luck 5: The companions have generally bad luck in the forest. Bombur falls into the stream of forgetfulness that has no bridge over it. When Bilbo climbs a tree to see how much further the forest extends, he cannot see anything but trees because they are in a small valley. Despite the bad luck, Bilbo wakes before he is poisoned by a spider and is able to help his friends.
Luck 6: In this section, the dwarves have two primary problems: they can't find the secret entrance and they don't know how to open it. Bilbo has the good luck to solve both of these problems. He finds the entrance at the top of a ledge and remembers the omens, predicted by Elrond, that will allow them to open the door. He does this just in time to alert the dwarves to the keyhole that is exposed in the ground.
Luck 7: The thrush happens to be around when Bilbo speaks of the dragon's weak spot. Bilbo also gets the dwarves to close the door to the tunnel right before the dragon rounds the side of the mountain and almost kills them. The same thrush flies to Esgaroth and tells Bard how to kill the dragon right at the moment when Bard is about to shoot his last arrow.
Luck 8: The dwarves would not have known of the death of Smaug and the advancing armies if Roac and the ravens didn't still live around the mountain. They are even more fortunate, because the ravens are still willing to obey the dwarves even if they don't agree with them.
Luck 9: Gandalf warns them about the coming attack just in time for them to set the armies in motion. The eagles appear when it looks as if the goblins are about to overthrow the other armies. When four armies cannot overcome the goblins, Beorn appears and rushes into the melee. He kills the leader and causes disarray among the goblin ranks. Bilbo is knocked out and he does not get seriously wounded throughout the battle, as he lies on the ground.
Luck 10: When Bilbo happens to tell Gandalf that he has been very lucky, Gandalf laughs for he does not think that there is such a thing as luck. He tells the Hobbit that everything that happened turned out that way because it was meant to, not because of some odd sort of circumstance.