Depending on the complexity of your taxes, the Form 1040 that you are using may require you to fill out worksheets to determine the number to enter on your tax return. You are not required to provide any worksheets to the IRS with your return, but you should keep the worksheets with the rest of your tax return documentation to mitigate any problems in the future.
It is important to recognize the distinction between worksheets and schedules. A tax worksheet is an IRS guide to assist you in your calculations and are primarily for your records. For example, in the event the IRS questions an entry on your 1040 form, you would refer to the worksheet you used to calculate that entry to back your number up.
Schedules, however, are not like worksheets; they must be filed with your tax return. Schedules are forms required by the IRS for specific types of income or deductions on your tax filings. There are many types of schedules. For example, Schedule A is the form on which taxpayers itemize their deductions; Schedules C and C-EZ are used for self-employment income reporting. These are filed with your tax return in order to provide a complete and accurate return to the IRS.
The IRS has suggested requirements for the length of time you should keep your tax returns and records associated with the return. The IRS suggests that you maintain your tax records for three years from the date you filed your tax return or two years following the date you paid the tax for that return, whichever is later. If you file any claims for losses resulting from worthless securities or bad debt deductions, you are instructed to keep those records for seven years.
The IRS suggests keeping your tax records for these time frames because they are equal to the statute of limitations for any actions relating to the returns. In the event there are any questions or allegations relating to a specific tax return, the IRS wants you to be able to rely on your documents as evidence. You may determine that you forgot to include certain deduction claims, and you may wish to amend your returns to claim the deductions and receive a tax refund.