GUIDING PRINCIPLE
The less supportive the environment, the more I need to document; the more supportive the environment, the less I need to document.
The intent of documentation is to provide an accurate record of what you did, when you did it, and why. It is useful to have in a Supportive Environment and genuinely essential in light of accusations, innuendos, and rumors that frequently occur in a non-supportive environment.
Would you have the facts readily available if you were being interrogated by an boss angry about a lost file or a missed deadline? Most people don't!