There is no right or wrong number of words that you should incorporate in a blog.
If you look at Pat Flynn‘s blog, they are sometimes in the region of 5000 words. It’s the same for guru’s Social Media Examiner – they also have long articles. But when you look at the King of content marketing, Seth Godin, his blogs only reach around 300 – 500 words.
In my opinion, the key is to get your point across without waffling. Appreciate that people have limited time nowadays, so get to the point quickly. Don’t string out your blog with waffle just to reach that magic 1500 word limit. A blog needs to be as long as it needs to be to get the message over loud and clear.