Discords
Formerly all discords were prepared, and Monteverde’s innovation of taking the dominant seventh unprepared was held to be cataclysmic, but in modern music almost any conceivable discord may be taken unprepared. We have grown so used to this now that we think nothing of it, still, whenever it can be done without sacrificing something more important, I think even a dominant seventh is better prepared.
It is only the preparation, however, of discords which is now less rigorously insisted on; their resolution—generally by the climbing down of the offending note—is as necessary as ever if the music is to flow on smoothly.
This holds good exactly in our daily life. If a discord has to be introduced, it is better to prepare it as a concord, take it on a strong beat, and resolve it downwards on a weak one. The preparation being often difficult or impossible may be dispensed with, but the resolution is still de rigueur.