The Tax Cuts and Jobs Act of 2017 (TCJA), broadly, lowered income tax rates for individuals and for businesses starting with the 2018 tax year. One of its biggest changes is to the standard deduction, which has substantially increased, while many deductions have been trimmed or eliminated.
Another reason for increased focus on the standard deduction is the newly reduced number (or value) of itemized deductions. State and local tax deductions now are capped at $10,000 ($5,000 for married individuals filing separately). Miscellaneous itemized deductions, such as unreimbursed employee business expenses, investment advisory fees, and estate planning fees can no longer be deducted. The mortgage interest deduction is now limited to $750,000 of total debt, effective for new mortgages in 2018.
Medical and dental expenses, meanwhile, can now be deducted for expenses that exceed 7.5% of a taxpayer's adjusted gross income (it was 10% in prior years). The percentage limit for charitable cash donations by an individual taxpayer to public charities and certain other organizations increased from 50% to 60%. If you are unsure how changes will affect you, seek the advice of a tax professional.