The numbers/numerals thing is a "cool tool for those who knows it".
I don't use it because I wasn't taught it or anything much else & I go out of my way to avoid the progression conventions that are, almost, inextricably tied in with it.
Those conventions exist for good reasons of course: Root/home, movement, floating, resolution etc.
The iv/4 system can be used without being caught up in them, and being a self taught/amateur is one of the easiest ways to avoid being "caught", but there're reasons people say things such as in David's quote,""Hey are you sure you want to go to the V so fast?" There're very strong cultural/training/expectation reasons that are tied into the common chord progressions. Pachelbel REALLY deserves some of the residuals.

After the 1st six taught me in 1976 by my college room mate, (so I could play along to a song I wrote the lyrics to & he the melody/chords), I learnt additional chords by discovery - sometimes moving a shape around and otehr times simply putting fingers in places. As a bass player for a few years before that I was, and still am, quite comfortable "writing" based on single notes and chromaticism.
The way I use chords is based on how I hear them together. Sometimes that matches a common progression. Eventually I learnt the names for most of those discovered chords, (I was past 35 when I found out that the two note "chords" I sometimes used were 5ths/power chords - I've lead a sheltered life), and can type them into BIAB to create "songs"...I've also restricted myself to using chords I can play.
I keep my harmonic vocabulary limited and I work within them and try to avoid the obvious.
I am a bad example of songwriting though and I know that many of my songs give extremely well trained musicians & music teachers headaches because of my failure to provide a "tonal centre" or to stay in a key or for "borrowing" chords that aren't supposed to be borrowed.
As I have a regular audience of just me I'm happy to work with what sounds right to me.

Here endeth my sophistry.

Last edited by rayc; 07/24/22 10:26 PM.
Cheers
rayc
"What's so funny about peace, love & understanding?" - N.Lowe