I've grown a few different kinds of beards. Here is the longest one, from just a few years ago, going past the natural neckline:
From a little later that same day, here is a result of a slight trim of the sides (leaving the front untouched), to show the natural neckline more clearly:
My natural neckline, like many men's, sits closer to the clavicle ("collarbone") than to the jaw-neck crease. It contributes well to the bulk of a long beard. Unfortunately, my beard, when long, made many neighbors and some family members uncomfortable because they associated it with pejorative stereotypes. Therefore, when I want a short beard that sweeps forward and downward from the ears to the chin, I have to maintain a shaved neckline, like this:
Here is the circlebeard from the end of May:
It did get as long as the natural neckline a few weeks ago, but I was setting vertical back edges, not the angle you see here from the mustache to the jaw-neck crease. The vertical edges caused a problem: No set of hairs was present to tame the sideways waves under and beside the chin, which I've seen on myself and on many men's pictures here.
On me, at a certain medium length, that wave is an outward, backward, upward curl on each side, like the little "canard" wings at the front of the Rutan (sp?) design for the one-seater airplane with the rear propeller, too comical for jobs that fail if customers or young students find any distraction in my appearance. The morning a few weeks ago when the wave popped open on each side after the shower and would not submit to a turned-action brush or comb job even while damp, I trimmed it back. Perhaps a hair-dryer treatment with a brush would have worked, but I do not wish to depend on a hair dryer.
I decided to shorten the goatee part for now, set a slight neckline for now, add the small angle from the mustache to the jaw-neck crease, and then let that angle part grow as long as the chin hairs, hoping to restrain the wave as the chin hairs lengthen again. I wish to be free from needing to maintain a neckline, even on a circlebeard.
My big-mustache experience in the recent long beard was frustrating. Most of my mustache arcs straight forward and down, and the ends and connectors curl both toward and away from the mouth. It defeats stiff wax in two hours, and I don't like tasting hair-styling glue in my coffee. If you have an outward curve or curl in your mustache, take full advantage of that rare blessing! This time I am trimming the bottom edge of the mustache just enough (a trim is overdue right now), while giving more freedom to the outward curves in the ends and connectors.