Are you a skilled and experienced horse owner who is capable of judging farrier work? I don’t mean to insult you implying that you aren’t, but if you are, look at the farrier work of other farriers in your area. If you are not educated enough to judge farrier work yourself, try to educate yourself to the point that you can form an opinion, even if you can not do the work yourself. To educate yourself, find Doug Butler’s book, “Principles of Horseshoeing”. After reading at least some of this book, you will be able to have a clue what to look for in terms of trim and shoe fitting, enough to ask some intelligent questions.
Search out horses that farriers other than your own work on, and inspect the quality of their work on other horses. Your current farrier does not need to know that you are doing this… you are just looking. And judging.
If you can identify the issues that you feel you are having with your current farrier that are making you think you might need to do a farrier change, search for a better job from someone else BEFORE committing to anything, or anybody. If you find a job that you like better than the one from your current farrier, you can make the switch.
IME, (married to a farrier for 30 years), your opinion and criticism and input is not going to change the job your farrier does… because he/she thinks they are doing it right, and have been doing it this way for X # of years, and you haven’t. They aren’t going to change because YOU say so. And they aren’t going to appreciate your opinion, as a “non-farrier”, whether you are right or wrong in your opinions. They will do the job they do, as they think is correct, no matter what the client says or thinks. So, if you find a farrier whose work you think is better suited for your horse, you will change farriers… which is usually not an issue for your previous farrier, they don’t usually care, have plenty of clients who come and go for a variety of reasons. They won’t take it “personally”. And if you end up regretting the new farrier and want to switch back again, all you have to do is make the phone call to your previous farrier to book an appointment. It’s OK.
This way, you do not have to risk your own horse’s soundness to “test out a new farrier”.
Also, make sure that you form your OWN opinion about a farrier job, don’t take someone else’s opinion as fact. I’ve seen popular coaches and trainers who don’t have a clue about farrier skills, and can’t figure out why their horses are all lame, with horrific farrier jobs that they can’t recognize. Vets too. Educate yourself enough to form your own opinion.
Good luck, it can be scary out there!