The specific answer to that question is left to the interpretation of the reader. Part of Frost's intent in writing the poem was to create an opportunity for each reader to consider how s/he approaches and makes decisions about where to go or how to live.
It appears that the narrator felt the less traveled road had "perhaps the better claim" for being chosen because it "wanted wear." The narrator's observations were that time and circumstances "had worn them really about the same," but the one looked as though it had been used less frequently. For whatever reason, this lack of usage appealed to the narrator and brought about the decision to take "the one less traveled by."
The selection is not made without some second thoughts and wondering if the decision was the correct one, as the narrator recognizes that s/he probably won't actually be able to return and travel the other pathway. However, the narrator is willing to deal with "all the difference" resulting from the choice that was made.
The following was posted in eNotes by tiff72 enoter on March 10, 2009 under the topic of The Road Not Taken and offers proof that Frost's poem was about himself and a serious life choice he had made in his past.
"On one occasion he [RF] told of receiving a letter from a grammar-school girl who asked a good question of him: 'Why the sigh?' That letter and that question, he said, had prompted an answer.
Amherst Mass April 1925
"Dear Miss Yates:
No wonder you were a little puzzled over the end of my Road Not Taken. It was my rather private jest at the expense of those who might think I would yet live to be sorry for the way I had taken in life. I suppose I was gently teasing them. I'm not really a very regretful person, but for your solicitousness on my behalf I'm
your friend always
[Finger, L. L.: "Frost's 'The Road Not Taken': a 1925 Letter come to Light", American Literature v.50]
Robert Frost chose to live an austere life and devote himself to his creative writiing. This fact is evident in many of his poems, such as "Mending Wall" and "Stopping by Woods on a Snowy Evening." In the letter quoted above he makes it clear that he was writing about himself in "The Road Not Taken." He says, "It was my rather private jest at the expense of those who might think I would live to be sorry for the way I had taken in life." The poem is about himself. The other metaphorical road, the one not taken, might have led him into a career that would have offered a more comfortable lifestyle (i.e., more money). He might have gone into banking, or trading in stocks and bonds, or into insurance or advertisiing. With his brains and education, he could have made a fortune in a big city like New York. He was aware of the opportunities he was giving up in order to live a life not unlike that of Henry David Thoreau, another New Englander. A person who wishes to devote his life to creative writing has to be prepared to make sacrifices--and Frost knew it. He writes about chopping wood for his own stove, about repairing his own stone wall, and about traveling in winter in a horse-drawn sleigh. The austere life he chose provided the subject matter for much of his writing. A lot of readers relate to Frost and to "The Road Not Taken" because everybody has to make hard choices in life, including choice of a career. Frost believed that any writing had to be dramatic in order to be interesting. He makes his poem dramatic by representing his career choice as a conflict at a crossroads in the woods requiring a decision.