I am a self employed musician and I spend anywhere between 10 hours to 16 hours a week with a guitar over my shoulders. As I've gotten older, I have had to see a chiropracter to get my back straightened out each week or else I can sleep well, stand for long, or continue to work. This expense is related 100% to my profession and is a necessary expense in order for me to work, much like a hair dresser would need a floor mat that provides comfort as they work, or an arm brace to combat tennis elbow. Is this deductible on my schedule C? Would a massage chair or heating pad be deductible? If so, why not a Chiropractor visit?
Chiropractor fees are a deductible medical expense and not a regular and customary expense for the occupation of a musician. That’s just the tax law. A heating pad and arm brace are deductible medical expenses also. You can only deduct a total amount of medical expenses greater than 7.5 percent of your AGI and only if you itemize.
Business Expenses have to be both ordinary and necessary, meaning common and accepted, to be deducted as a business expense.
A chiropractor visit would be a personal medical expense deductible on Schedule A if you itemize. If massage chairs and heating pads are ordinary and necessary for guitar players, then you could deduct those on Schedule C. Those would not be medical expenses, but a doctor's visit would be. Also, if you pay for health insurance, you may be able to deduct the premiums (Self-Employed Health Insurance Deduction) without having to itemize.
See Pub 535 for more details.