hmmm it is an interesting conversation. When I think about the whole processes I go through I guess it is kind of simillar.
I don't finish the writing of the song before I record though. I know this might sound a bit wierd but as soon as
an idea forms I start to record... Whether it be the chords on guitar or keyboard for a verse or whatever. Once I have laid that down
I can start adding things, vocal melodies, more guitar, bass or whatever. That often leads me to where the rest of the song might go.
The idea can be done in just a few minutes but then the rest of the song and the building process can indeed take me many weeks or even
months.
In the mean time I usually throw it on a disc to listen to in the car. Listening to it over a longer time period allows me to hear things that I
realise are worng or sometimes will give me new idea's of what I could add to it OR take away.
I tend to add layer after layer of instruments, vocals etc so experiment with many different melodies. At the end I have a piece that I can reduce (get rid of
all those melodies and instruments that don't fit or no longer match the feel of the song.
I saw Eric Clapton talking about this. He said that when he was in the studio listening toi George Harrison writing and recording "Wah Wah", that Harrison
painstakingly came up with a riff that had multiple guitar parts. Then he cut it back to just one riff because that's what he thought suited the song the best.
I have been given the same advice by other class musicians too. Build, build build, add more and more, try this, try that... you can always take it away, but if you don't
put it in in the first place you will never know what it COULD have been.
The trend these days is to be minimal or do things acoustically. That's fine but can become very boring.
If you only have one instrument then you are missing out on a lot of tools musically like counterpoint for instance. You can't really have much counterpoint going on
with an accoustic guitar and nothing else. Not that having counterpoint in a song is a neccessity but if you want it to remain interesting then it helps.
I'm not dissing the minimal approach and some songs suit it. But I see it as a cop-out to take that approach every time.
So to sum up. I think sometimes if you are lucky, you can write a whole song in 5 mins, but if you want to be all it can be then spending more time on it and really pushing it to full potential
is more often than not a must.
I usually find myself moving on to something new, or re-visiting an old unfinished one for a while so that when I come back to my present creation it will sound fresh to me
and I will much more easilly be able to hear what needs to be done.