It varies considerably from one individual to another. Sometimes it is years between episodes. Sometimes it is much less. Some sufferers may have only one full-blown manic episode or even none in their lifetimes.
I don't know, to be truthful, but since many family members of bipolar individuals never develop the disorder, I would expect that there would be some variability in symptom patterns for those family members who do develop the disorder.
As far as I know, and from my experience, the patterns of bipolar individuals can vary markedly. My daughter is a slow cycler, while I was a very rapid cycler. My grandfather was said to be primarily manic, with very few periods of depression. It was during one of those periods of depression that he suicided, however. My daughter is primarily depressive. I cycled so rapidly, it was kinda difficult to tell which mood was more prevalent, but it was probably depression, as I think back on it.