Struggling with certain bits of vocal not cutting through in your mix? Sidechain can help with that, and be a neater way of dealing with the problem than automation.
For example, one bit of backing vocal or perhaps a bit of a spoken word is just not cutting through. Apply a compressor that has a sidechain feature to your main vocal group, then use the one you want to stand out to duck it. Just remember, make sure it’s not in the same group, ducking itself!