[resonator]

Most of the changes we (I work in a platform team) make may perhaps only modify a couple of lines of code, but took significant time and effort to reach.

As an example, we recently decided to adopt the use of Kubernetes CPU manager. The actual change was modifying the resource requests for some applications. That part of the code is highly dynamic as apps change and are retuned over time. To store the decision to use CPU manager in a commit message or even a Github PR would not be appropriate -- it's discoverability is too low compared to its importance.

Unlike Git commits or PRs, our ADRs are a rich archive of well thought out decisions with all the rationale that went into making them. We can easily see which ones remain relevant. But what I think is the most important is we have all the information we need to change our decisions and we do. We no longer fear making change because we might not have all the context, or we forgot, or the person who made the decision quit last year.