Many taxpayers decide whether to take the standard deduction or to itemize. The standard deduction is a fixed reduction to taxable income available to most filers, while itemizing requires listing eligible expenses — mortgage interest, some medical costs, charitable gifts — with records to back them up. Choosing is often a cost-benefit judgment: if your total itemizable expenses exceed the standard deduction, itemizing may lower tax; otherwise, the standard deduction is simpler and often faster. The decision also changes if your life changes during the year (marriage, buying a home, major medical costs). This question focuses on what “itemizing” means in practical terms, and why records matter for that option.