Photo: Bokeh / Tomedia. Person Taking a Photo at Night.
There is a very efficient way to ruin a useful explanation. Decide it needs to be 2,000 words before you work out what it needs to explain.
You can usually tell when this has happened. The answer is somewhere in the page, surrounded by introductions, definitions nobody asked for and several sections saying roughly the same thing. There is plenty of content. Reading it takes far longer than the question deserves.
I wrote a very large book about SEO, so I am aware that I am in a slightly awkward position to complain about length. The reason the book is large is that it deals with a lot of separate questions. A page about one of those questions still has to earn the time it takes to read.
An average is not an instruction
SEO studies often compare the length of pages that rank well. You can take an average from a set of results, put it in a presentation and make it sound like a target. That doesn’t establish that adding words caused those pages to rank.
A detailed comparison may need more space than a definition. A technical guide may need examples and exceptions. A page with opening hours can do its job very quickly. Combining all of those into one target gives you a number while throwing away the reason anybody opened the page.
Google explicitly says it has no preferred word count in its guidance on helpful content. That should make this conversation shorter than it often is.
I would still inspect the pages already appearing for a query. They can tell you what sort of answer people might expect and what has been covered. I would use that to understand the job, then decide whether I have something useful to add. Copying the average length tells me very little about whether I’ve done that.
Depth needs a subject
Covering a topic properly might mean explaining how something works, when it fails, what it costs or how to choose between the options. Those details belong when the reader needs them.
They don’t belong merely because a content template has a section for each one. A definition doesn’t necessarily need a buying guide attached. A service page doesn’t become more useful because it includes a history of the industry before allowing somebody to make an enquiry.
Think about what the visitor will have to do after reading. Have you given them enough information to do it? If they are comparing options, have you described the conditions under which each option makes sense? If they are trying to complete a task, can they follow the steps without guessing at the missing part?
Those questions can make a page longer. They can also reveal several paragraphs you can remove. I would rather make that decision against the reader’s task than a length requirement handed down by a tool.
Let people find their section
Some explanations do need to be long. Once they are, structure becomes part of making them usable. Give sections headings that say what they contain. Keep the examples next to the explanation they support. Add a linked contents list when there are enough sections that somebody would benefit from jumping between them.
The contents list is there to help someone move around. It doesn’t need a story about unlocking a special ranking benefit to justify its existence. The same is true of a comparison table or a labelled diagram. Use the format that makes the information easier to understand.
Also allow the answer to appear early. You can explain the conditions afterwards. Forcing someone through an elaborate introduction because you would like their visit to last longer is a fairly poor way to reward them for choosing your page.
Open one article on your own site and remove the passages that repeat the promise in its title. Then check whether the answer is complete. I go further into this in The Big Book of SEO on Ephemera, which you can buy and use as a reference without turning every page you write into another book.