It's good practice to always leave a short comment about what work we did in the edit summary (the text entry field just above the Publish changes and Show preview buttons).
This helps other editors tell at a glance what you have done. Sometimes, without an edit summary, your work may be considered thoughtless or belligerent, and be undone.
Summaries are also especially useful when reviewing page histories, to see without the need to load and visually parse each diff, what each of possibly thousands of edits changed.
