I like metaphors and similes, but they should be used sparingly. I think there was a Story Embers article a while ago that said they should do double duty–describe the thing you’re trying to describe and show off your character’s voice, like Rose said. I read a book recently–Brother’s Keeper by Julie Lee–that had a good amount of similes and I think they fit the story well.
Metaphors I tend to use and prefer to see them used in conjunction with a theme. Sort of like symbolism, I guess. Maybe that’s just because my metaphors tend to be long. In fact, now that I think of it, I’m not sure whether my story I’m thinking of had metaphors or if it was just symbolism.
Most of my metaphors and similes just happen as I’m writing. And I get very excited when they do.
"For He knows our frame; He remembers that we are dust." - Psalm 103:14