Because you acquired the home by a gift, your basis usually is the basis that your parents had in the home (what they paid for it, plus capital improvements they made over the years). It may be difficult to reconstruct this information, but their initial cost may be available (e.g., published on Zillow).
A business method of accounting requiring income to be reported when earned and expenses to be deducted when incurred. However, deductions generally may not be claimed until economic performance has occurred.