When is a quote more than just a quote? When it's a blockquote. And when is a quote a blockquote? The Blue Book § 5.1 and ALWD § 47.5 agree the magic number is 50 words or more. ALWD and The Elements of Legal Style § 4.9 both also direct use of a blockquote if the quote is 4 lines or longer of typed text; but that rule appears to be less universally accepted -- and is irrelevant for my tip today, so I've chosen to ignore it.
in Word there is a dead-simple way to measure if you've come up upon the 50-word-threshold. Highlight your quote (without citation) and look in the bottom left corner of the window.
Bam, the length of the selection is displayed. My quote here is 80 words so I'm applying my blockquote autostyle to it.