When doing basic system administration or infrastructure the goal is to be as painless or headless as possible, one you forget about.
Amendments to accommodates mistakes or changes to a successful or semi-successful infrastructure will require you to still remember how the system was set up or know the system to maintain and debug it.
Even a successful infrastructure might require change due to pivots, system changes or just evolution of a product.
When you don’t have basic documentation in the form of a README.md, wiki or self documenting systems you will have a hard time finding how you solved something and might require software archaeology.