You must save all of your receipts for your deductions for 3 years after filling your taxes. If you are audited, you must provide proof that you indeed had those expenses. If you cannot support your deductions, you may be assessed a tax liability for each unsupported deduction.

There are tax professionals that are available to help, of course for a fee. So it is important that you try to protect yourself to the fullest by making sure you report your tax information as accurately as possible. Using a service that guarantees accuracy and therefore reduces your risk of being audited is your best solution, other than paying a tax professional a lot of money.