In Hindu mythology, God has given boon to demons for meditating. Generally, how long the different demons had to meditate to make god visit them.
Wanted to know general estimate of time to meditate, to get god visit us.
The question is
How long to meditate for god to come and visit?
Rig Veda III.31.9 says, Angirasas sat for months to gain the WISDOM
They sate them down with spirit fain for booty, making with hymns a way to life eternal. And this is still their place of frequent session, whereby they sought to gain the months through Order.
Sri Vasistha Kavyakantha Ganapati Muni, was a disciple of Sri Ramana Maharshi. Vasistha Kavyakantha Ganapati Muni belongs to the race of giants who crowded in the narrow corridors of the first four decades of the 20th Century.
When Ganapati was staying in Kashi he came to know that there would be a great assembly of Sanskrit scholars in the famous city of Navadwipa in Bengal. On the advice of his friends he got a letter of introduction and started for Navadwipa.
There he passed the difficult tests in extempore Sanskrit prose and poetry with an effortless ease that stunned his examiners. Unanimously, they conferred the title 'Kavyakantha' (one who has poetry in his throat) on him forthwith. He was then 22 years old.
Like in ancient times, Ganapati desired to acquire immense strength and power through the practice of austerities and mantra japa. Though married at an early age, which was the custom of the times, Ganapati, when hardly 18 years old, set out and wandered from one sacred place to another, residing in places like Bhuvaneshwar, where he performed his tapas.
The Muni approached the Virupaksha Cave where Brahmanaswami lived on the 18th of November 1907. Prostrating before the young Sage, he pleaded with a trembling voice:
"All that has to be read I have read. Even Vedanta Sastra I have fully understood. I have performed japa to my heart's content, yet I have not up to this time understood what tapas is. Hence, have I sought refuge at thy feet. Pray enlighten me about the nature of tapas."
For fifteen minutes Sri Ramana Maharshi silently gazed at the Muni. He then spoke:
"If one watches where the notion of 'I' springs, the mind will be absorbed into that. That is tapas. If a mantra is repeated and attention is directed to the source where the mantra sound is produced, the mind will be absorbed into that. That is tapas."
Upon hearing these words of the Sage, the scholar-poet was filled with joy and announced that this upadesa was entirely original and that Brahmanaswami was a Maharshi and should be so called thereafter.
When a Spiritual giant like Sri Vasistha Kavyakantha Ganapati Muni, with so much determination and wisdom, could not understand how to proceed, after performing so much of tapas, I do not think it is such an easy subject to explain with.
Finally, my answer will be - No, it is not possible to say.