Keith here with a super quick one: No Code is Sacred Code. Sacred code oftentimes is the sign of an engineer with too much influence. Maybe it's even someone who other engineers feel uncomfortable sharing feelings with.
Sometimes sacred code is a sign of a serious technology deficit: areas of code, maybe they moved real quickly early on in the lifecycle of a product and have become disaster. Unspoken words, no engineer will touch it...
How do we resolve this? At Dimension Software, every Friday is a day where we sit back and reflect-- Retro --to visit technology debt. This allows us to incrementally eliminate tech debt so there's never a point in the future where so many engineers working on a single project are so overwhelmed with the amount of sacred code that it's difficult to make forward progress.
We address this Weekly, Incrementally and on Fridays. This process allows us to move forward with rapid pace. Everyone feels groovy about the code being written and lighter on their toes. Personal health, team collaboration-- everything increases in qualilty.
Definitely take strides to eliminate sacred code in your codebase. Engineering becomes so much smoother. Your team will thank you.
-Keith