In Yoga, a minimum of 200 hours of training is required before one teaches. Are there a required minimum number of hours of meditation before one can reach Enlightenment? Can one person meditating for inner peace and positive change contribute to healing the world's problems?
I have heard suggestions of how many minutes per day one should meditate (12, 30, 60) and how many days of silent retreat one must partake in to come to Enlightenment. I have heard many people express an "aha moment" when they found their Enlightenment and other people say it evolves over time with the deepening of their practice. I do believe meditation is the path one takes to reach the summit of Enlightenment. And, I am only at the trailhead of my ascent.
I've not considered myself Buddhist. Even though I often said when my children were toddling, if there was a Buddhist school, that's where I'd send them. Now, my daughter is studying the psychology of Buddhist meditation at Naropa University and my son is doing a thesis on the influx of Yoga in Western cultures.
I questioned the powerful influence of monks spending their life in isolation, living out of touch with the happenings in the "real" world, could make towards our world's problems. I chided tenderly and respectfully, calling the enlightened souls living in caves or up on the mountaintop "Fools on the Hill." I thought that if I were to live constantly in retreat from the endless list of everyday tribulations existing in our world -- well, I'd be sitting in meditative bliss. But how would I then be of service to anybody other than myself? How would this contribute to making the world a better place?
A few years ago, I likened myself to the protagonist in Kissing Jessica Stein, looking at my watch every twenty seconds to get through three minutes of meditation. I sought a Buddhist therapist to find my inner peace. Then, one day, my Buddhist therapist gifted me with a little box holding a mala blessed by the late yogi Chatral Sangye Dorje Rinpoche. I had no idea what to do with mala beads, or who HH Chatral Rinpoche was. I learned the beads were to hold while I meditated and with each bead focus on thoughts of compassion and loving-kindness for all beings. I like to believe I was bestowed this treasure box and these magical beads because of the values I hold near and dear, those the same as HH Chatral Rinpoche's. He was a strict vegetarian and a determined advocate for animal welfare. I like to believe my therapist thought the transfer of Rinpoche's energy into my hands would provide intention and a continuation because he knew I would hold the mala and feel the blessings from Rinpoche's spirit and continue his wishes for all living beings. 
To save animals from slaughter or any mortal danger,
With entirely pure motivation and conduct,
Is without doubt a practice to be taken up...
Lamas, officials, monks, nuns, men and women,
In all the places over which you have control,
Exert every influence and do all within your power
To release animals and ransom their lives,
While encouraging others to do the same.
-- from The Benefits of Saving Lives, HH Chatral Rinpoche
At the closure of 2015, HH Chartral Rinpoche passed on to parinirvana. I never met the esteemed man; I never traveled to India or Tibet. But, I understand how one enlightened person, living in retreat, practicing meditation -- in isolation, in a cave, on a mountaintop -- can impact somebody thousands of miles away and his wishes can be carried on. Today, when I sit... in my isolated world, holding my blessed mala... I think of our beautiful world, tribulations and all. I hold the energy from HH Chatral Rinpoche to take care for all animals and our planet.
In part, I jest when I ask how many hours of meditation and retreat are required to reach Enlightenment and to attain Buddhahood. I relate it to wanting to run a marathon and sitting on your sofa reading Born to Run -- you won't get very far unless you put on your running shoes (or even barefoot like Abebe Bikila) and take your stride outside. I started my interest in the Buddha nature through literature, but I realized by practicing meditation was when I began to understand. The words of HH Chatral Rinpoche teach me that what is required is to begin and then to practice with authenticity of intention and with compassion for all. Some people say compassion for all, to reach awareness towards an infinite number of beings, seems vague and abstract -- understandable -- consider cultivating focused attention in a benevolent manner towards any beings that come into your field of awareness.
You might remain sealed in strict retreat for months or even years,
But if you fail to make any progress in the state of your mind,
Later, when you tell everyone about all that you did over such a long time,
Aren't you just bragging about all the hardships and deprivation?
No matter where you stay -- be it a busy place or a solitary retreat --
The only things that you need to conquer are mind's five poisons
And your own true enemies, the eight worldly concerns, nothing else,
Whether it is by avoiding, transforming, taking them as the path or looking into their very essence,
Whichever method is best suited to your own capacity.
There's no better sign of accomplishment than a disciplined mind,
This is true victory for the real warrior who carries no weapons.
-- from Words of Advice, HH Chatral Rinpoche
Self-development is important to help solve the world's problems. It begins within oneself. We are all interconnected. If you change yourself in a positive direction, those near you will feel it and hopefully be influenced and then they will influence others and so on. This is how I came to be influenced by HH Chatral Rinpoche. I know the "Fool on the Hill" holds the wisdom to make the universe a better place... but the fool on the hill/sees the sun going down/and the eyes in his head/ see the world spinning round. *
*Paul McCartney, 1967.