Let's look at a block of "No Action Needed" reviews:
What constitutes a 'reviewed' review?
- Leaving a comment
- Up voting a comment
- Up voting the post
- Down voting the post
- Flagging (or close voting)
- Editing the post
If something is likely to be closed, even if one doesn't agree with the closing philosophy leaving a comment suggesting for how to refocus the question in a way that isn't likely to get closed. Alternatively, editing it to try to make it something that won't get closed.
For a no action needed it means that none of the above reasons are applicable or needed:
- Not bad enough to down vote
- Not good enough to up vote
- No existing comments to up vote to help suggest a better question or improve the existing answer
- No additional guidance needed to help improve the post (note: likely in conflict with 'not good enough to up vote' - it is unlikely that both of these are true, but may be the case)
- Grammar, spelling, and formatting of the post are acceptable and don't need any work (note: it's a good thing to click 'edit' to see the actual markdown and make sure there isn't formatting that has been lost that needs to be brought back out like a numbered list or line breaks)
- On topic without any need to migrate or suggest a way to make it narrower, less opinion, or need to refocus it from an existing off topic reason.
- Not a duplicate of another post (do a search - especially the case with questions, many new users don't know of existing questions)
- Not posted elsewhere on Stack Exchange (example: "This was posted on Stack Overflow as well, where it was closed and has now been deleted." from https://softwareengineering.stackexchange.com/questions/241598/cms-desktop-app-control could have either been up voted or researched and written themselves)
If you don't want to check these things, either hit skip or don't do the First Posts review.
Selecting 'no action needed' means that someone else can't do the review to check these things, completing it and giving guidance to the new P.SE user that may help them have a more positive experience on P.SE and Stack Exchange as a whole.
This is in part an issue with the system. The First Post review queue, by its nature, has binding votes for every review. This isn't something that people are always aware of, but the First Post review (and late answer) are both review queues that one should approach with all the seriousness of a diamond mod because there's no redo or community safety net for these reviews.