[jjice]

I wish I did. I currently work at a startup with our core offering being ETL, so I've learned along the way as we've continued. If anyone has any, I'd love to hear as well.

Keeping raw data when possible has been huge. We keep some in our codebase for quick tests during development and then we keep raws from production runs that we can evaluate with each change, giving us an idea of the production impact of the change.