Oh, reincarnation is not one of the unanswerable questions. Buddha is mentioned in the sutras as saying things about his own previous lives and previous lives about others as well. And when people died, he often said things about their next lives too, and said things about the effects on their future lives.

So that’s different from the unanswerable questions where he just said nothing in response.

As an example, there’s the story of Pukkusati who met the Buddha, not knowing who he was, and had a long conversation with him, at the end of which he asked to become a monk. Buddha said that first he needed to find a begging bowl and robes and when he went off to find these, he got gored by a cow (that’s Pukkusāti in the Dhātuvibhanga Sutta). Then Buddha’s companions asked him what happened to Pukkusati after he died and Buddha explains that he has taken birth in a pure land.

There are differing teachings about what a pure land is, as I was taught then this is not really a heavenly state - it’s not just a place where you experience nothing but bliss. That by itself wouldn’t make it a pure land, just a fortunate rebirth which gives you a holiday for a while within Samsara. As I understand it, a pure land is rather a rebirth in which everything you encounter bears the message of the path of the Buddha (for some practitioners this very life can become a pure land in that sense). Anyway, he said that he will take a rebirth in which everything he encounters is part of the path of the Buddha and then that he would realize Nirvana in his next life in that place.

However, though he often said things like this, he didn’t say that we should blindly accept what he says on those matters, or anyone else, either. Rather it’s the idea that at some point we’d be able to see such things for ourselves. But such things are extremely hidden. They aren’t impossible to see or things that are unanswerable like the unanswered questions. But they are very hidden for most of us.

Still, I think it does help to think in terms of these vast timescales and ideas of past and future lives. Not as a creed, but rather as something to help open our minds to possibilities. That’s because you are pretty much bound to have some views about what happens when you die, even if unexamined. Even to have a view “I don’t know” it is still a view. I think that goes both ways - if you belong to a culture where past and future lives are taken for granted, still, it can be useful to recognize clearly the basis for that view - to say “I believe that because I’ve been told it by my parents or because of my faith in the sutras” or whatever it is and to recognize “I don’t know this from my own experience”.

And to have an open mind about things you don’t know. For instance, however much ones faith in the sutras, it might be that ones understanding of them is a simplification, that one is missing some subtlety in the ideas. It might be that Buddha would have taught in different ways to present day Buddhists. The Kalama sutra suggests that the path is one where you recognize clearly what you know and what you don’t know. Including things that seem logical or accord with ones own preferences, to examine them on the basis of your own experience, especially the results of putting them into practice, and on the basis of the advice of wise friends.

So, these vast timescales I think help with patience along the path, make it easier to relax, to have some sense of humour about oneself.

But if you have too much focus on that you can be lazy. But meanwhile there are things one can see far more easily than this, such as the reality of suffering, and that even the most blissful states, including the most refined meditative states, don’t last for ever. These are things that can be easy to see, and recognizing impermanence too. Many Buddhists would say that this is where we should start, and that’s how Buddha taught the four Truths, at least as presented in the sutras, to start with the truth of Dukkha of suffering but also of impermanence of even some of the greatest forms of bliss and even higher states than bliss possible from meditation.

And - I see the teachings on rebirth as not so much as a dogma, as an interesting world view that can help one to be more open minded about what one knows and doesn’t know about what happens after one dies or happened before one was born. Because we nearly all have world views about what happens when we die, hard not to have some such, from our parents, our culture, our friends etc. So it’s like that, another world view that may be helpful to consider as a possibility, given that we are bound to have one anyway.

And meanwhile the sutras also do have stories in both directions. Many stories about followers of the Buddha who became arhats in that very lifetime. Also in the Mahayana traditions many such stories. So with that vast timescale, it’s still possible that for some this may be the very life in which they finally wake up :).