Every change discussed on this forum should satisfy three conditions before it goes near a machine somebody depends on.
- The original value is recorded before the change is made.
- The change has a defined purpose expressed as an expected observable effect.
- There is a tested path back to the original state, and it has been tested on this machine rather than assumed.
The screening safety writeup covers what this looks like in practice, including which categories of change are excluded entirely because they cannot be cleanly reversed. Screening safety writeup.