To be deductible, a business expense must be both ordinary and necessary. An ordinary expense is one that is common and accepted in your trade or business. A necessary expense is one that is helpful and appropriate for your trade or business. An expense does not have to be indispensable to be considered necessary. It is important to separate business expenses from the following expenses:
A duple meter metronome that is useful for 2/4, 2/8, 2/2 (cut time), and 6/8 when it has two beats per measure.
1 The terms duple, triple, and quadruple refer to the number of beats in a measure. 2  The term simple means that each of these beats can be broken into two notes. 3  For example, 2/4 time is classified as simple duple. '' 4 Duple'' refers to the two beats per measure.