JACKSONVILLE, Fla. -

Some tax forms are even called EZ, and most basic ones may be.  But once you have to itemize or add in any type of extra income, experts say you're very likely to make a mistake, and that can really cost you.

"If you make a mistake, especially with some of the credits, that could be a thousand or a couple of thousand dollars that somebody is missing out on," explains Kathy Kellar with H&R Block here in Jacksonville.
We turned to HR Block to find out the most common errors people make so you'll know what to double check if you do your tax returns alone.

Kellar says hands down, the biggest mistake is people not taking full advantage of the available deductions.  "The education credits, the adoption credits, taking the child tax credit, the additional child tax credit, childcare credit," says Kellar.  On the otherhand, people often make the mistake of deducting items that aren't allowed.

Also,  people searching for jobs often forget or don't know that a lot of those expenses can be deducted.  Or, people end up claiming the wrong types of bills, purchases and fees.  If you do that, it can cost you in a different way if you get an inquiry or you get audited by the IRS.

"Once you've made a mistake, you don't know how to correct it and you think what do I do, who do I go to, and that's when you need to come to someone and find out what you need to do to get this corrected," says Kellar.

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