U.S. Internal Revenue Service Form 1040A, the short form of the individual income tax return, and its instruction booklet change every year because federal tax laws that govern the rules, computations, allowances and deductions change regularly by acts of the president, U.S. Congress and the IRS, according to Intuit Turbotax. Income tax forms only address the tax laws as they exist at the time the filing is due.
Every year, the IRS publishes tax forms and instructions for individuals and businesses to file federal income tax returns that are only good for the indicated year. Taxpayers who need to file taxes for a prior year must obtain tax forms for that specific year. The federal tax code and its regulations are complex, dealing with everything from allowable deductions to the estate tax percentage. Tax breaks expire or are cut, tax percentages change and rules are adjusted by Congress every year, according to efile.com, so having a set of tax forms that takes all of these changes into account is imperative.
For example, a natural catastrophe in one part of the country may lead Congress to pass a law that allows people affected a special tax break. This break may only be applicable for the year of the event. The IRS must change the income tax forms and instructions to reflect this new tax break and change the forms again once the break expires, explains Intuit Turbotax.