I should talk more about introducing a horse to a saddle. How I would do it anyway. There are lots of ways to get them used to the existence of the saddle. Some leave an old nasty saddle on the fence or in the pen. I would do that if I had one. Willow liked to chew on my old nasty saddle when I was getting her used to it. Some ask the horse to work everywhere else and rest only where the saddle is, so it becomes kind of a buddy, a home base, a good place to be. Some just throw the saddle on. The way I did it today, because it worked with the pad I was using so I continued it with the saddle, was that if he tried to walk away from the saddle while I approached, I continued to approach, basically circling him around, until he stopped. Then I didn't throw the saddle on, I released pressure by stepping back, putting the saddle down. Eventually the release of pressure was just me stopping, not moving away. Then the saddle went on, off, on, off, on more vigorously, jiggle and smack the leather, wiggle the saddle, jiggle, wiggle some more, take it off. Do it all over again on the other side. Then walk with the saddle on his back. Whoops, slight spook when his body bent to make a tight turn and the saddle didn't bend with him. Nothing serious. He never dumped the saddle. I didn't ask him to move around quickly, I didn't want him to dump the saddle. If he had dumped it we'd have worked through it but I'd prefer he didn't.
I have to say my elbows were killing me most of the day, and my arms were worn out from all that saddle hefting, and it isn't even all THAT heavy. Probably 25-30 pounds. Some roping saddles weigh about 60 lbs. I'd have found a different way to work with a saddle that heavy!
Now to the most important thing. When I do cinch up the saddle the first time and every time, I cinch it up! I don't make it nice and comfy and loose. I do it slowly, I don't just yank it on up, but I do tighten it up all the way. Why? Because if he were to start bucking, which I encourage (more on that in a minute) that saddle could flip around to his belly or even just his side if you're using a breastcollar. Talk about terrifying! I've heard of many horses that were "ruined" by such an accident. Broke through fences, just about killed themselves, and would never wear a saddle again. (I think the right training and trust could "cure" them, but that's a different subject.) As they say, "An ounce of prevention is worth a pound of cure." Now, I wasn't worried about that at all today, because there was no cinch. If he bucked or freaked out, the saddle would fall off but it wouldn't stay attached to him and eat him alive. No big deal.
Next, once the saddle is on, I will either "round pen" him or longe him. I prefer a round pen but I don't have one right now. I want him to feel that saddle moving with him and not moving with him and doing whatever it's going to do, at all gaits if possible, turning, etc. Basically just get him comfortable with it. That's what I meant when I said I would encourage him to buck. If he's going to, I want him to do it when I've set him up for success, not with me on his back or when it's a bad situation.
A lot of people already know this, sorry if it was redundant to you, but I thought it was an important subject to cover.