You may usually begin to file your taxes once the IRS can accept the returns of that tax year, which is generally at the end of January. The date may be a little different every year, so it is better to refer to the official opening on the IRS site. There are some circumstances that may cause you to defer the time of filing such as having to provide some forms by your employers or financial institutions. On the other hand, when you are claiming some credits or estimating some of the data of the previous year, then you are also prepared to file as soon as it opens. There is also the option of extensions that will provide additional time.