Near the start of the fourth season of Babylon 5, we learn that Sheridan,
after his 'death' at Z'ha'dum, can live for at most twenty years.
He comforts Delenn about this, telling her that twenty years together will be a miracle when they're in the middle of so many crises that they could die any day. But of course Delenn (even after her transformation?) is Minbari. How bad it is for her to marry someone who'll only live 20 years surely depends on how long her own expected lifespan is. Since Minbari are pretty much "space elves", I always imagined them having very long lives, but I don't actually remember anything about their lifespans being stated explicitly.
How long do Minbari generally live for?
If your answer requires spoilers from Season 5, please mark them as such.