Does it matter how many words you write in each blog post?
Yes, for many people, it does.
Some writers set themselves a target number of words per day, as a good habit. Whether your target is 500, 1000, 2000 or even more words, a lot of writers love the discipline of hitting a daily target.
Some other writers are aiming for a specific word count simply for marketing purposes. It's generally thought that Google gives a higher rank to longer posts, so long as they're interesting. So many SEO experts recommend you write posts between 2000 and 2500 words.