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.
Time signatures are separated first by whether it is simple or compound. Then by whether it is a duple, triple, quadruple, quintic etc. Duple meters are grouped in 2.. 2/2, 2/4, 2/8 are all examples of simple duple meters. 6/8 would be an example of a compound duple meter as it still a grouping of two, but has 6 beats in one measure.