there’s more history feeding these kind of decisions as well. When you’re writing - as Shakespeare did - in blank verse, you have to end the line after 5 iambic feet (ten syllables). Shakespeare is considered the king of this because of how he does it.
“Friends. Romans. Countrymen. Lend me your ears.”
10 syllables but the speaker is trying to attract the attention of a large crowd. He’s counting. Friends (1). Romans (2). Countrymen (3). Lend me your ears (4).
In Othello, Iago says
<span style="color:#323232;"> For when my outward action doth demonstrate
</span><span style="color:#323232;"> The native act and figure of my heart
</span><span style="color:#323232;"> In complement extern, 'tis not long after
</span><span style="color:#323232;"> But I will wear my heart upon my sleeve
</span><span style="color:#323232;"> For daws to peck at. I am not what I am.
</span>
Note how the line breaks are sense breaks too. So Shakespeare is skillfully obeying the meter while also lining up the sense of the underlying message.
There’s even the same tension/release device of the undressing from the above poem in the last two lines (when I wear my heart on my sleeve… … …it gets eaten by birds!)
When you don’t have a strict meter (in the same way that modern music nowadays doesn’t obey the Sonata form, or the symphony form) you can be more inventive with how you’re using form and format to create your work.