Yesterday I wrote about songs that use only one chord. One-chord songs aren't for everybody; they might or might not fit your style. But any songwriter can make good use of one-chord sections of a song.
There are four parts of a song where it's common and conventional to stick with one chord through the whole section.
Verse part A. In songs with formulaic 2-part verses, part A sits in one place for a while, until part B comes along and gets thing moving. There's no better way to sit in one place that to stay with one chord -- typically the [one] chord.
Chorus. Especially with short, hook-laden choruses, you might see a whole chorus stay on one chord. Since the chorus is the musical core of a song, its single chord is the [one] chord by definition.
Bridge. In a certain mid-20th century tradition, the bridge was called the "middle 8" -- and it was exactly eight bars long, and usually eight bars of the [five] chord. Thank goodness we've moved away from that terribly limited formula! But you'll still sometimes hear a bridge that sticks on the [five] chord the whole way through.
Introduction. Sometimes the beginning of a song is just a groove that repeats until the singer comes in. There's a word for that kind of repeating bit -- it's called a vamp. And a vamp is often just a single chord. Similarly, a song's fadeout is sometimes just a single-chord vamp. And if you need a little connecting piece between verse 1 and verse 2, sometimes a few bars of the [one] chord will fill that space perfectly.
I can't tell you how many times I've struggled with various combinations of chords while writing a song, only to finally realize that I only needed one chord after all. It's the desire to make things interesting that trips me up. Of course we want our songs to interest the listener. But if we make everything interesting, you know what? It's boring. Some parts of the canvas need to step back, to be background, white space, or texture. That's why our songwriting toolbox need to include rests, monotones, repetitions, and one chord.