Lord Krishna as His childhood Vrindavana form and Lord Chaitanya Mahaprabhu, both only appears "once" in a day of Lord Brahma or "once" every 8 billion 640 million human years.

This is the blissful way street sankirtan should be done by both men and women, boys and girls, even dogs and other animals can join in as we have seen.

This is the way Srila Prabhupada personally trained us telling us ''Harinam Sankirtan'' is the greatest gift to this world!!

In this degraded age of Kali-yuga, which means hypocrazy and quarrel, Harinam Sankirtan is Lord Caitanya Mahaprabhu’s special gift to this world and is very rare.

There are 1000 Kali-yuga’s in one-half day (day-time only) of Lord Brahma's time, it therefore takes 4 billion 320 million human years for 1000 Maha-yugas to pass from Sunrise to Sunset.

Then in the other half of Brahma's day which is night time from Sunset to Sunrise, there are no Maha-yugas created because while Brahma sleeps, a partial annihilation happens that also takes 4 billion 320 million human years.

So adding the time of a day and the time of a night of Lord Brahma's 24 hour day, Lord Caitanya ONLY comes ''once'' every 8 billion 640 million human years.

A Maha-yuga is a cycle of Satya, Treta, Dvāpara and Kali-yuga’s which happens during Lord Brahma’s day-time period from sunrise to sunset.

Lord Caitanya's appearance in just one Kali-yuga, the same Kali-yuga we are in now, is very, very rare.

So this means Lord Caitanya does not appear in the other 999 Kali-yugas however other Vishnu tattvas also appear during Brahma's day.

A 24 hour "day-night" period of Brahma happens over a period of 8 billion 640 million human years

There are no yugas during Brahma’s 12 hour night time period while he sleeps, the time between Brahma’s sunset and sunrise is when this material universe experiences a partial annihilation happens over a period of 4 billion 320 million human years.

So one ''day-night'' 24 hour period of Brahma equals 8 billion 640 million human years as already explained.

Lord Caitanya therefore comes “once” in a 24 hour day of Lord Brahma (only during the day-time)

And Lord Krishna ''in His original childhood Form'', also comes just "once" in a 24 hour day-night period of Brahma (also ONLY during the day light hours when the 1000 Maha Yugas exist

Lord Krishna in His original childhood form, appears at the end of ''one'' Dvarpara yuga out of every 1000 at the end of a Dvāpara-yuga.

It is important to understand that Krishna never leaves Goloka Vrindavana therefore, His Vishnu tattva expansions plays out His Vrindavana pastimes on earth and also kills demons that do not exist with Krishna in Goloka Vrindavana in the Spiritual Sky.

As, already explained, many Vishnu tattva expansions of Krishna also appear many times during Brahma's 12 hour day-time when the 1000 Maha-yugas exist. But Krishna as His childhood Vrindavana form only appears "once" in a day of Lord Brahma.