If you’re planning to start a business in retirement, then get right on it. Preliminary start-up costs can’t be deducted. Instead, the deductions have to be spread over 60 months. On the other hand, once you’re “in business” many of your outlays will be deductible expenses. What’s more, you can be in business before you have any revenues. Thus you should position yourself as being in business as soon as possible, even before you have paying customers. Advertise or have business cards printed to solicit sales. If you can show that you’re operating a business, you can deduct your expenses.