How long is the lifetime of spirit in between?

Sorry in advance for so many questions. Please feel free to answer one or all of them. :) I have a few questions. Just looking for opinions or experiences.

After we die, how long do we stay in spirit? On average..
What really happens during our 'life' as spirit? Do we meet 'god' or 'higher power' and make plans for our next life in form?

I've been through some pretty intense experiences already during this life.. not sure what is real or what is just in my head?, but one thing is when I was in a car crash that I was lucky to get out of, I remember seeing a glimpse or thought of heaven. I don't claim it was real or anything, but it was pretty surreal and scary.:( So this is part of the reason I have questions right now...

Some say we have to go through a period of remembering, and facing our decisions during life. I kind of agree with that. But after that, do we always come back to earth as human? or as any intelligent life form? Do we continue with the path that we had as human? Does our spirit die, in order to take birth in a body? Is spiritual death painless?

Again, just looking for opinions or personal experiences. Links to knowledgeable sites are welcome to. Thanks. :)