Word Count for Blog Posts: How Long Should Yours Be?
fastwordcount.comi guess around 2500 words are good enough
Some Say 4000 words are good for SEO
Nothing's worse than a_forced 4000 words where you can see the author scrambling to make it just _a little bit_ longer.
I believe there's a natural "right" length to most posts, and with experience you learn to gauge if you're over that length or not.