What discounts?
Almost all income is taxed in retirement just like when you are working, except for Social Security and withdrawals from Roth IRAs. Your SS benefit is not taxed if it is your only income. If you have other taxable income, then your SS benefit may also be taxed. If you perform work after you are retired, your income from working is subject to social security and medicare tax, even though you are also collecting a benefit. If you have income other than social security, you file a tax return like normal and calculate whatever tax you owe.
For 2025-2027, there is a special extra tax deduction for seniors that reduces your taxable income and will reduce your tax even more than normal.
