Quote Originally Posted by pops1 View Post
Sherry, here is the simple rule to use. Play a 7th chord whenever/wherever you like the sound, in the piece you are playing. If you like how it sounds play it, if you don't, don't. That is what it really boils down to.
That may work some some styles of music, but in other genres like jazz you could not just sub a dom7 chord for a minor 7 or a major7 chord.