Self Realization is nothing but knowing the reality about yourself. Reality that you are not this physical body but someone beyond this body. Reality that you are a Soul which is part & parcel of that omnipresent Super Soul which is called Brahmn, Kutastha Chaitanya also, which is immortal & which is present in all the creation.
Now How Long it takes for Self Realization? To realize your true self, you only need to change your thought & have a firm faith, realization that you are a Soul & not that physical body which perishes in time. Once you move away from body conception of yourself & move towards Soul conception of yourself, then you have Self Realization automatically. Such Self Realization can actually occur in a flash of time only if you believe yourself to be a Soul than body. Other wise, it may take, years, many births also till you get out of this conception of yourself as a physical body. So believe yourself to be a Soul which is part & parcel of that omnipresent Super Soul called Brahmn & you shall get Self Realization at this very moment.
Here below a a story in which a man asked Gautama Buddha the same thing:
Young Man: Master how long will it take for me to achieve enlightenment?
Gautama Buddha: It all depends on you......
Young Man: If I put in ten hours of meditation every day how long will it take?
Gautama Buddha: Maybe ten years
Young Man: What if I put in fifteen hours meditation?
Gautama Buddha: Maybe fifteen years
Young Man; [getting irritated] What if I meditate for twenty hours?
Gautama Buddha: Maybe twenty five years
The young man was almost infuriated.
Young Man: I cannot understand your logic—the more effort I put in, the more time it will take—this is ridiculous, Please explain.
Gautama Buddha: As long as you are fixated and obsessed about your goal you will not achieve it. Just do spiritual practice without one eye on the goal. Let events take their shape.
Recently Nobel Laureate V. Ramakrishnan, an Indian American said in an TV interview that he embarked on his research not out of a desire to win laurels but out of curiosity to solve a scientific problem. He was not working with one eye on the Nobel Prize.
So ‘’It does not matter what you do in life. Let you aspire to be the very best in terms of excellence in whatever you do."
In other words EXCELLENCE ought to be our ideal and everything else ought to be a side effect.
Bhagwat Gita also teaches us to do work in this way. Doing work in such a way, is called "Nishkama Karma". "Nishkama Karma" just means, no egoism in our action, no expectation of any gain or reward but doing your work effectively. It is also that : “You have a right to action but never to the fruits of action.” Below verses of Bhagwat Gita Explains that only.
ma phalesu kadachana
ma karma-phala-hetur bhur
ma te sango ’stv akarmani" (Bhagwat Gita: Chapter Two verse 47)"
"Sri Krishna said to Arjuna: You have a right to perform your prescribed duty, but you are not entitled to the fruits of action. Never consider yourself the cause of the results of your activities, and never be attached to not doing your duty."
"Yoga-sthah kuru karmani
sangam tyaktva dhananjaya
siddhy-asiddhyoh samo bhutva
samatvam yoga ucyate" (Bhagwat Gita: Chapter Two verse 48)"
"Sri Krishna said to Arjuna: Perform your duty with an equipoise mind, abandoning all attachment to success or failure. Such equanimity is called Yoga."
So just do your work with your 100% involvement & dedication & derive pleasure out of doing such work. You yourself shall then see that when you care for the work only & not it's final outcome, you work most effectively. Doing work in such a way is only called "Karma Yoga".
Read also...............It's Journey not the Outcome that matters
Read also.............What is Karma Yoga?