I am not an accountant. What follows is a result of my study of accounting procedures and the tax code. Use this material as a starting point and consult your own tax professional for specifics on your unique situation.
If you file a Schedule C with your family's Form 1040, all business expenses will be deductible.
If you don't file, they won't.
Why would you want your business expenses to be deductible? Because you reduce the income on which you must pay taxes. The smaller the business amount, the smaller the total amount on which your family's taxes are calculated.
This amount of taxable income is called Adjusted Gross Income or AGI. Your tax strategy is to reduce your AGI as much as legally possible. The smaller the AGI, the fewer dollars you will owe in taxes.
The AGI is the number on the last line of the front page of Form 1040. This is the origin of the expression "the bottom line."
Business deductions include books and printed music (most accountants think CDs and mp3s also qualify here), journals/magazines, office supplies, postage, photocopying, convention expenses (transportation, hotel, meals, rental car, tips, etc.), perhaps concert tickets (considered as an educational expense needed to keep current in your field - - but talk this one over with your adviser), insurance, mileage when your car is used for business purposes, entertainment expenses, and so on.
You also can depreciate equipment used in your business, such as a computer, software, printer, bookcase, filing cabinet, desk, and so on. Depreciation is a kind of deduction you claim over a period of several years rather than all at once. ("All at once" is called a write-off.)
Under certain circumstances, you can claim write off a purchase that normally would be depreciated. Your accountant will know all about "Section 179 depreciation."
As this deduction can reduce your AGI substantially, it is very attractive.
There are two disadvantages, however. First, if you claim the deduction for office in the home, you will reduce the amount of money you may contribute to your retirement fund.
This is because the maximum retirement fund contribution is based on the number shown after subtraction for the home office deduction.
Second, claiming this deduction will reduce the amount of profit that is not taxed when you sell your home at retirement. The thinking is that when you downsize to move into a smaller home when you retire, you deserve a tax break on the profit. A certain amount of the profit is not taxed, but is excluded.
If you claim the office in the home deduction, the exclusion is reduced because you already had tax relief on that portion of the house's value.
Generally, taking the office in the home deduction is harmful in the long term: your retirement contribution is reduced and your tax liability when selling your home at retirement is increased.
Unless you are going hungry, I propose that the retirement money later is more important than the deduction now and that you should not claim the deduction for business in the home.
Consult your accountant about this very important deduction decision.
It's perfectly ok to be in the hole after your deductions have been taken. That is, not only do you not have a profit, but you've lost money being in business.
Even if you have lost money, file a Schedule C.
Just as having a profit on your studio increases your family's AGI, having a loss reduces it.
This is exactly what it sounds like: you make a little business out of your hobby so you can write off hobby expenses and thus entertain yourself at the IRS's expense. Naturally, the IRS frowns on this!
The IRS says you must have a profit in at least three of the last consecutive five years. If you can't show this, the IRS may say your studio is a "hobby business."
Other things on which the IRS looks favorably as evidence of a real business are:
If your income has been less than the deductions claimed and you engaged in few, if any, of the previous standard business practices, the IRS may ask you to convince them that your motive was profit, not recreation.
The specter of being declared a hobby business should not keep you from filing a Schedule C if you have a loss. Yes, you derive personal pleasure from playing the piano and from introducing your students to the same joy, but this does not negate the facts that you have advertised, have a separate checking account, have consulted an accountant, and so on.
Some expenses are unique to piano teachers. One of them is tickets to a concert. Some accountants feel these are legitimate business deductions (as education expenses) and perfectly legal to claim. Other accountants feel claiming concert tickets is a "gray area" and a deduction that might be questioned by the IRS. Because of this, they may advise you not to claim such a deduction.
Do not hesitate to claim as a deduction any expense you think is an honest business cost. Your accountant will catch anything out of the ordinary, and you can talk it over. In the end, however, the decision whether to claim something is yours alone, just as the monetary benefit from claiming unusual deductions is yours alone.