It is considered best practise on a wiki to leave an edit summary for every edit.

Leaving an edit summary when making large alterations or additions is especially important as the edit summary will help explain your edits.

Edit summaries appear in lists of changes (such as edit histories and recent changes special pages. This makes edit summaries especially useful when tracking a series of edits made on a page without needing to compare every individual edit.

Where to leave an edit summaryEdit

When you edit a page there is a box at the top or side of the article that states "Add a summary of your edit". Click the text in the box, or anywhere in the box and leave your summary.

What to writeEdit

The summary of your edit should be a description of what you're adding or changing.

Even a brief summary is better than no summary at all.

It should be descriptive of what you are changing, be it; adding additional content, removing significant content or altering the article.

If you are making edits based on a Forum discussion link to that discussion in the edit summary.

What not to writeEdit

• Comments on what you have removed or edited. Summaries such as "I don't think they said that" or "That's not how it happened" are not helpful in understanding your edits.
• Edit summaries are covered by our No personal attacks policy. Do not use the edit summary to attack other users' edits.
• Don't use the edit summary to be comedic about a page's content or what you are changing.

Minor editsEdit

If you check the minor edit check box then you are signifying that only a superficial difference exists between your edit and the previous versions of the page.

Even when making a minor edit it is best practice to leave a brief edit summary.

What is a minor editEdit

• Spelling and grammatical corrections.
• Typography and punctuation corrections.
• Fixing incomplete wikilinks.

What is not a minor editEdit

• Adding or removing content from an article.
• Adding or removing visible tags such as Stub tags or cleanup tags.
• Adding comments to a talk page or forum discussion.

Edit summary propertiesEdit

• Limited to 250 characters. You cannot type more than 250 characters, if you attempt to paste more than 250 characters into the summary box it will simply be cut off.
• Your edit summary will appear at the bottom of the Preview box when you preview an article.
• Wikilinks are rendered. So if you're enacting a decision made in the Forums place a link to that discussion in the edit summary.