Sorry, I suck at quoting, so I hope this makes sense.
In regards to your “yeah, I should be more consistent with my filly and two mares at home.” On one hand, I think horses who are at home tend to like us a lot and are pretty nice about helping us out (until they are not because all that liking everyone means they get herd bound… see below).
On the other hand, your being a tad inconsistent could be like making your filly into a Cat! You know what’s wrong with cats? It’s that when you try to show up teach them that life is unpleasant on the counter, they are smart enough to know that you, not the counter, is the independent variable. So they correctly conclude that “life is unpleasant on the counter When She Is Here And A PITA.” In other words, you can/should install great basics and a base-line level of “When I get serious and say so, you need to step up your obedience and focus.” IMO, we don’t need to have that all the time, but with these huge flight animals, we’d better have some of that experience of following orders in there. Depending on the horse, they might be the one that, like a cat, tests your authority every day so that you have to answer their test, every damn day. Others don’t need to constantly test the boundary and think about jumping on the counter. You’ll know which you have.
Also, I have discovered that a really nice test of the horse’s ground work (as well as a fun and useful skill) is my “sending him.” So, on the end of a 14’ long-ish rope, can I get him to walk out ahead of me somewhere? Can I fake/semi-line drive him somewhere from one side? Can I do that from the off side as well as I can the near side?
I like a horse to have this skill-- my ability to drive him out of my space promptly and calmly. We all need that button in a horse, sooner or later. If I don’t teach him that as A Thing, and someday he sees something scary on his other side such that he is tempted to jump into my space, I’m going to wish that I had developed his deep experience with putting his attention back on me, even as I’ll drive him sideways away from where my body is. The “get out of my space” button is needed. But the “I asked for your attention, ignore that thing and put it on my and the job (even if it’s simple because the horse is in hand” is an equally-important part of what will keep him from crushing you because, in the heat of battle, he forgot you were there.
We would not accept the level of “Oh look, a squirrel!” checking out under saddle as that is plainly dangerous. But the way I was raised in English world, we had much lower standards on the ground. You can regularly find grown-ass horses sometimes needed things like chains over the nose in distracting situations to keep them attentive. I am starting to wonder if that’s a training problem that we created because we didn’t bother to take the in-hand stuff seriously after we taught the foal to come along on our right side and we’d muddle through the rest of stuff we’d do on the ground with him.
Teaching a horse to be sent is pretty neat because horses that have had good ground work which includes your being able to turn them away from you, will allow you to line drive them forward and away from you, too. It’s nice because it’s a prelude to line driving that you can do on the fly without switching up any equipment or special preparation.
It’s nice because it lets you do some ground work in straight lines rather than always turning them. As an aside, I will say that I’m not a fan of drilling a horse on NH-style’s tight turns. Truth be told, I don’t think those guys do a ton of that every day or every week on their own horses, either. I’ll never take a horse to a 3-hour ground work clinic. I’m not every sure that horse’s get all of what they need from those tight turns or disengaging their hind end. Why can’t they get training from the contrast of switching direction? In that case, straight vs., say, a 90-degree turn makes the same point.
Sending a horse on a lead is a great exercise because again, on the fly or where the horse raises the question about something spooky and stop and work on that. It’s so cool to just answer the horse as he asks, stopping to exploit whatever training opportunity you happen upon. To the horse, of course, this comes across as you always miraculously being there to support him in each moment or situation. It’s even better if he’s the one who finds himself in need of support. If you see one of the above posts about how I suggested the OP might use an arc in ground work to have her horse stop, stand and think while facing the bad corner, just know that the ability to then stand back behind his barrel/out to the side and finally send him toward the object without you going first is a great end-point that you want to get to. Teach him that skill when he isn’t facing something repellant so that you have it to use when you want to make the point that he’s got to go where he’s told, even without the benefit of you walking there first. After all, this will be an existential crisis we expect him not to have when we are on his back and not there by his head to go first into danger.
Being sent on the end of a lead is a nice skill to have when it comes to trailer loading. You might have a nice enough trailer that you don’t need this and can walk him in, and you personally might have a great technique for loading him. But that might not be true for that horse for the rest of his life. IME, people have really different ideas about how to load horses and when the horse doesn’t get right on the trailer or know what their handler knows, things start to go bad and stay bad. I try to make a horse that will load into everything and load lots of different ways so that his breadth of experience can make up for a person’s lack of experience. IMO, knowing how to be be sent ahead is a basic skill that should be well-installed because of how often it can come into play with loading.
But again, the Being Sent skill is a nice extrapolation of ground work because it lets you make an interesting point about the fact that you can be in control or “with him” to help him, and in a training conversation, with your unstarted horse without having to be where he can see you beside him.