I first began to chant Japa, using the Mahamantra, when I was 18, I am soon to be 43.
I read the Bhagavad Gita and in it Srila Prabhupada explained that Krishna wanted us to chant his Holy names, that to do this is to associate with Krishna and great benefits would follow.
I had never seen Japa beads before and the old broken backed 'Bhagavad Gita As It Is', that I bought in a second hand store, didn't describe how to make them. I bought some very large wooden beads almost as big as golf balls. I strung them and tied them off and I began to practice chanting. My friends thought it a bit crazy, but no one attempted to dissuade me.
Through his book, Srila Prabhupada convinced me that chanting Japa was worth doing and this is the reason I started. I had no one to discuss it with and had no association with devotees except for Srila Prabhupada and his book.
In the purport of Bhagavad Gita, Chapter 8, Verse 5 - Srila Prabhupada says: "If one wants to achieve success at the end of his life, the process of remembering Krishna is essential. Therefore one should constantly, incessantly chant the maha-mantra—Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare / Hare Rama, Hare Rama, Rama Rama, Hare Hare.
I had no context to understand what I was doing but it seemed to me to be like this: Writers are writers because they write, joggers because they jog, singers they sing and the well-wishers and lovers of Krishna chant His Holy name.
When a writer writes it can be fulfilling and satisfying but sometimes it is difficult and tedious and nothing seems to work. I know this, I am a writer. Joggers say (I don't jog) that it can great, but sometimes boring and lonely as well as painful. Singing can bring elation and satisfaction but to obtain perfection as a singer is hard work (I do sing but people tell me not to.)
In my ignorance I considered that Japa would be similar. My mind is sometimes bored and it wants to think about something else. Sometimes my back aches or my legs pain and my body says we did this long enough already. Sometimes I can think up really good reasons not to chant my rounds. This is the way of our selves and our minds - they are not so used to being controlled by us in such a close and personal way as when we chant His names.
In the purport mentioned above Srila Prabhupada goes on to say "There may be so many impediments for a person who is chanting Hare Krishna. Nonetheless, tolerating all these impediments, one should continue to chant."
So when I was bored I thought well this is devotional service - I don't do it because it's a blast (although it often is), I do it as my sacrifice, as my offering. At these times I remind myself of the reason I took up chanting, it is because I heard and read that Krishna is pleased when I do it.
I didn't know anything about offenses or things of that nature. I just knew that Srila Prabhupada had told me this in the purport of Bhagavad Gita 12:6:7 "The process is very simple: one can devote himself in his occupation and engage at the same time in Hare Krishna, Hare Krishna, Krishna Krishna, Hare Hare / Hare Rama, Hare Rama, Rama Rama, Hare Hare. Such transcendental chanting attracts the devotee to the Personality of Godhead."
I still chant now - primarily because Krishna wants me to do it and so I chant for his pleasure. I chant because in Srila Prabhupada's books he tells me this is what Krishna wants me to do and that he is pleased by it - under these circumstances how could I refuse?