14. Bitcoin
Although part of the attraction of bitcoin is living off the grid, the IRS expects you to declare bitcoin income and it can be rather complicated if you made many transactions. The IRS considers bitcoin to be property (like stocks) rather than currency so you’re reporting capital gains.

15. Filing Late
Last, but definitely not least, filing taxes late is a common and costly mistake. If you realize that there’s no way you’ll be able to get it together by the fifteenth, you can apply for a six-month extension instead. The deadline for applying for an extension is also the eighteenth. Be aware—this is a filing extension, not a tax extension—you will owe the IRS interest on any 2015 taxes that aren’t paid by April 18 so this should always be a last resort for freelancers or anyone who may owe taxes at the end of the year.