For future income taxes, you don’t need to know anything about your traditional IRAs except the balance. All withdrawals are non-taxable.
For Roth IRAs, you need to keep track of direct contributions and rollovers/conversions if you are under age 59-1/2, because that can affect taxability of withdrawals. Over that age, the withdrawals are all non-taxable no matter what “class” of money they represent.
In general, I would keep all tax-related documents for 7 years. It would not hurt to keep just the tax returns for longer, if you have ever filed form 8606 or 5329.
