[e12e]

> How about program preferences and configs that get saved elsewhere by default?

Nothing goes (should go) elsewhere by default.

If you're wiping the distro and re-installing - you probably don't want to keep /etc anyway.

Fwiw Ubuntu in place lts to lts release upgrade should be solid. But sometimes you want start with new, contemporary defaults, or a different disk layout.

BTW with zfs, you can have a separate home (or home/your_user) filesystem, and not worry about allocating fixed space (thus running out of free space on /, but with more available in /home and vice-versa).