Some common reasons include: 1  a serious accident â such as a road accident, a severe head injury, a serious fall or severe burns. 2  a serious short-term condition â such as a heart attack or a stroke. 3  a serious infection â such as sepsis (blood poisoning) or severe pneumonia.
The definition of unnecessary is not needed. An example of something unnecessary is a bowl of sugar for cooking meatballs.
The expense must be ordinary. The expense must be necessary. It must be an expense as opposed to a capital expenditure. The expense has to be paid or incurred during the taxable year. The expense has to be in carrying on the activity. The activity has to be a trade or business activity the part for.