When working out what business deductions to claim this tax time, it's important to remember the three golden rules: 1. The money must have been spent for your business – not a private expense. Most business expenses are deductible but you can't claim a deduction for private expenses, such as child care fees and clothes for your family. 2. If it's a mix of business and private use, only claim the portion related to your business. For example, if you bought a computer for your