Perhaps this is understood by the points already made about sometimes needing to re-work a song, but I don't think that anyone in this discussion has mentioned yet whether it's important to him or her to get input from another person [or other people] as to whether that person really feels [or thinks] that the song "works".

Mot that I consider myself a songwriter, but I've revised the lyrics and/or tunes of some children's songs & chants that I've written {whole cloth} and adapted {from traditional game songs & chants} based on my observation as to whether the lyrics and tunes of these songs were well received by groups of children I worked with.
Some of these revisions included or at least started with these children's comments about the songs, or my observations about whether the group of children accepted the song as is. And some of these changes to lyrics & tunes included the words that a child or children made through their mis-interpretation of my words, or through the suggestions that they offerred.

I'm wondering how important to the song writing process for folks here is having input from others?