Basically, it depends on your goals. But also on your subject and your community.
If your main goal is that your articles are read in full then you should try to write posts with a maximum of 400 words. Longer articles tend to cause your readers to just read some little portions (if any) of your complete post.
If you pursue that your articles reach the widest possible dissemination, being shared a lot on social networks, you should write longer content. According to some studies, articles with more than 1500 words are shared more than shorter articles.
Typically, this is because longer articles cover topics in greater depth, providing a bigger number of relevant information. That’s why these articles are so often seen as reference articles.
Goal: SEO Ranking
If you pursue to get a good ranking of the posts in your blog, then you should write and publish articles with more than 400 words. Google rewards the longest posts because it believes they are more elaborate and provide more value than shorter articles.
You must strike the right balance between the different goals and different lengths to success. Once you do that, you can set Nelio Content to consider the length of your content and warn you if you do not reach a minimum.
By default, the criterion followed by Nelio Content is that the length of a post should be at least 700 words and ideally be 1,000 words long. This way you can be sure that the length of your entries is the minimum recommended for SEO.