The Myth of Down Migrations

My "down" migrations get exercised when I need to switch feature-branches in local development.

I'm OK with the idea that they almost certainly won't be needed after the feature has been in production for X months, but there are still short-term benefits, such as being a kind of executable code-documentation for when DevOps finds out something goes Horribly Wrong with this week's release, and you're trying to hit "undo" within a relatively short time period.

On longer time frames, you'll probably make a new differently-forward migration script, but the old one can still be very handy to have as a reference.