How long is the lifetime of spirit in between?

Quite a few questions for one thread.
A few brief comments.

I recall contacting spirits who died in the civil war. and also from Antlantean time....who were "trapped" here and sent home by my teacher. I'm certain they were unaware of time as we perceive it.

I'm also curious precisely what one experiences between earth lifetimes but have no significant information at the moment,

Know for a fact many youngsters now come from higher evolved "planets" and volunteered to come here to help in this rapidly changing time.
it was suggested I did as well, by my teacher, (and to learn as well)

I definitely suspect I've been here at least twice but don't
anticipate coming back.

Never experienced "heaven" but I've visited realms of egoless light in psychedelic enhanced meditation, a few decades ago.

For those who question reincarnation, I often bring up Mozart, who was composing at age 4.
He obviously learned his craft someplace, previously. Even though his father coached him, he quickly surpassed his fathers talent. Though it was suggested he may have come from another planet-dimension by my guidance. A possible example of "picking up where one left off" in terms of vocation. THOUGH I can imagine one applying spiritual understanding to any art one has not practiced before.

I've also frequently heard of children reincarnating within the same family lineage ....