Quoting 624582:" We rent. The only amount I have contributed to charity is about $150 (clothes, not cash). We live in ... [snip!] ... deductions are higher than the standard, right? And you can only use the amount that is above the 2% of your income, right?"
You cannot tack on the itemized deductions with the standard, so you are correct, the only time you should itemize is if your itemized adds up to more than your standard deduction would be.
Now, what is relevant is AGI---adjusted gross income. There are things that can deduct from income before you get to the point of taking into account itemized deductions. The threshold is what percentage of AGI you have to be over, before your expenses matter. For medical, it is 7.5%. Unreimbursed employee expenses (job travel, licenses and fees, etc), tax prep fees, investment expenses, etc.) are subject to 2% threshold.
Casualty or theft losses have their own rules. Taxes paid (property tax, state income tax, state sales tax), interest paid (mortgage interest, points, qualified mortgage insurance premiums), and charitable contributions (tithing, cash or property donations) have no such threshold and are taken without having to be above a certain percentage of AGI.