I've seen it countless times - a rider goes on their forum or page of choice and says "my horse has -insert training problem here-, what bit/gadget can I use to fix it?" Then the comments are rapidly filled with people listing their contraption of choice to band aid the problem and make life easy for the rider. Here's the problem: riding isn't easy. Trying to make it so will only make things worse for your horse. Today, I want to discuss what are valid reasons for seeking a new bit/bitless bridle, and what aren't. We'll start of with the invalid reasons.
Invalid Reason #1) My horse has a training problem. Most common combinations include a Waterford for a hanging horse, a hackagag for a horse who drops his shoulder, twisted wire for a horse who runs, and draw reins for a horse who puts his head in the air. Ironically, all of these things can be corrected by improving the horse's responsiveness to the seat and balance on the hind end. As a bit cannot teach those things, but will hurt your horse into reasonably complying, a training problem is an invalid reason for bitting up/changing bits.
Invalid Reason #2) Well everyone else uses one. Very common in the western world, where people think they need a "western bit". While there certainly are divisions that require a curb, many riders who sit in a western saddle believe this somehow decides what hardware they need in their horse's mouth, and that they MUST have a curb for this reason. As the saddle does not impact the mechanics of the bit, this is an invalid reason for bitting up/changing bits.
Now let's discuss a few valid reasons for changing your bit.
Valid Reason #1) This is more power than I could ever reasonably need. Hypothetically, I could get on Sid right now in a wonder bit and he would do fine. But that is putting him in far more pain than his snaffle without any valid reasoning. If they go well in a smooth snaffle, there's no reason to continue to use the big curb or the twisted wire just because "it's what you've always used". That is why having too much hardware is a valid reason for changing bits.
Valid Reason #2) I want to diversify the signals available to me. This is the most common reasoning for employing a double bridle, as it allows for (effectively) double the unique cues that can be transmitted to the horse.
Valid Reason #3) My horse seems uncomfortable in this equipment. Common signs of discomfort are mouth gaping, hanging on the bit, flipping the tongue over, refusing to soften, and other behavioral problems. Rather than using a flash or a harsher bit, work with your equine dentist to find a bit that will best fit the shape and size of your horse's mouth.
Valid Reason #4) I am extremely reluctant to put this one on here because I know I will get 40 some comments saying "oh well my horse is definitely that one" so let me preface that with this: in my 15 years of riding, and sitting on hundreds of horses, I have only seen one valid application of this scenario. This reason is the necessary bit up to "bring the horse down to earth" in order to work down to a lesser bit. For example, if I were to jump on a horse right now who had been constantly ripped on in a saw tooth bit, he would likely be effectively numb to a smooth snaffle, and while I would try it, if he were to reject it I would try progressively stronger and also different styles of bits (i.e. A hackamore, single joint vs double joint, etc) to determine the bare minimum of severity required to get a response. From there, I would immediately begin working backwards to re-soften the horse. This bitting up is NOT a permanent change, and if it lasts for more than a ride or two without going down, you need to more deeply examine your training.