The decision is simpler than it sounds: use whichever deduction method gives you the larger total benefit.
What the standard deduction does
The standard deduction reduces taxable income by a fixed amount without requiring you to list eligible deductible expenses one by one.
What itemizing does
Itemizing means listing qualifying deductible expenses individually, such as certain medical costs, mortgage interest, charitable gifts, and state and local taxes within applicable limits.
Why most people take the standard deduction
For many taxpayers, the standard deduction is larger than what they could produce by itemizing. It is also simpler, which matters when the benefit difference is small or nonexistent.
When itemizing becomes more relevant
Itemizing may be worth checking when you have unusually high qualifying expenses, large charitable giving, substantial mortgage interest, or other deduction categories that push you past the standard amount.
Bottom line
Do the math once. If itemized deductions do not exceed the standard deduction, the decision is basically made for you.