I would often come up with a theme, get the first line down with the verse and chorus, and ad-lib with my first recordings before the net (I only have that link of my early recordings here for reasons of going back to standards).
With my newer stuff, I start over again often because I screwed up in the vocals and expect to to get the memorization of the lyrics and vocals down.
It is a matter of repitition I guess.
But I don't like sounding too rehearsed.