We have a four-generation picture somewhere: My great-grandomther, my grandmother, my mom, and me as a baby. My great-grandmother died two or three years after that picture was taken.

I don't think that's likely to happen again. My grandmother's 90-something and not in the best of shape (Alzheimer's). There's also a tendency on my mom's side of the family to have children relatively late (30s). While there's longevity on that side of the family, not so much on my dad's side.