So much of good mixing is good arranging. Part of your job as a mixer is to keep the listener engaged, and you do that by creating movement and variety throughout the song. One easy opportunity for this is to use multiple vocal delays and switch between them.
The Short And Long Of It
One thing I like to do is to create a really short delay in the verse, giving the vocal a lively, raw sound. And then open it up to a more epic style echo in the chorus to change up the feel entirely. It’s easy to do, but it can make all the difference.