All my life I've written songs. About 200 + now. 90% of them were done within an hours time. That hour was about three hours after I should of been asleep.
I'm a night person, I hate sleep, and am at my most creative when I'm exhausted. Why? I have not one clue.
I use to write down the song then go to bed. When I'd wake up it was like looking at someone elses scribbling. I can't tell you how many songs I've lost because of imporper saving.
Words to songs come at any time, day or night, but music come when I'm really tired, to tired to write it down now.
I've solved that problem though. I carry a small mini cassette with me everywhere I go, just like a writer will carry a note pad, or an artist will carry a drawing pad.
I even carry extra batteries, and tapes. One never knows.