The music I work on in my DAW isn't pre-planned at all. I write tunes for acoustic guitar sometimes, but that's just tinkering with my guitar and remembering good stuff which, through a bit of solo jamming and experimentation and filtering, ends up as a tune over a span of days or weeks. At the DAW, I'm all about experimentation and evolution and I take full advantage of all of the modern technology at my fingertips. This means I will jam, compose, arrange, sound design, mix and edit continually in a circle according to where my creative thoughts take me.
For instance, I'm currently working on a piece that started as a rough fingerpicked riff played on electric guitar, then this was translated to MIDI with Melodyne, edited in the piano roll and generally messed around with until I had a nice plunky keyboard part which pleased me. And then it was expanded into an 8 bar pattern, and a few drums added, and a bass, and some more synths, and generally bounced back and forward on and off for a period of weeks. At some point I decided that I didn't like the original keyboard sound, so I designed a new one, and that immediately sent me off on a completely new tangent in which all other parts had to be changed to suit the vibe of the new sound. Extra bits were added during completely whimsical sessions of idle tinkering, and before you know it I was working on a whole new section of the tune and the original section was laid to the wayside. A few more sections later and the piece was at 8 minutes long, and then new parts were experimented with to tie the existing sections together. Entire sections were moved around and rearranged on the timeline, and before you know it, the original keyboard part was relegated to a small section later in the piece. However, the MIDI of this part was used throughout all of the new parts and mess with, turned upside down, reworked and manipulated in bizarre ways using strange Reaktor instruments, and then this led to more evolution, more tinkering, more rearrangement and more sound design.
Before I knew it, the piece was 20 minutes long, had almost 100 tracks, something like 40 synths in the synth rack (only a few turned on at a time and used to generate and record audio), hundreds of clips all over the place (some stored in "storage" tracks hidden from view) and dozens of markers all over the place. And all the time, I'm doing rough mixing with EQ's and compressors to get a nice sound going as inspiration. They're inserted at will, hundreds of them, and swapped out and messed with continually. New "bridge" sections are added to transition one part to another, and oftentimes these turn into entire sections themselves, and I'm adding another 32 measures to the project here and there, perhaps deleting some as well. Right now I think I'm about 60% of the way there, but parts are continually being reworked and added to and edited so who the hell even knows.
This is a completely nuts way to work, and I'm pretty sure I have some ADHD and this is why I end up working this way, but the point is that it would have been completely impossible for someone like me to work in such a whimsical way 30 or 40 years ago. Unless they were rich enough to own a fully fledged studio, and even then they would only have access to a fraction of the tools I have at my disposal on my computer. So while I can completely see the benefit of the old workflows described above with their careful planning and preparation and foresight, I thank God that affordable tools exist these days which allow complete and utter scatterbrains like me to have a crack at it