Occasionally I am asked "what do I need for my expenses such as medical or work related expenses"
My answer is two-fold
1. For me to prepare your tax return, I need a summary, or running total of your expenses that are paid. I do not need the receipts, but if you are audited, you will need to provide them to support your deduction.
2. For your records, you need to keep the receipts and documentation that support your deduction. You need to keep these for at least 3 years, I suggest 7 years.
It is important that you do not "double-dip" For example; health insurance paid by your employer is already not taxed (on your) W-2; therefore, do not include this in the running total of your medical expenses, you do not want to double deduct your expense.
As a tax practitioner, I am not required to review every receipt used to substantiate your deduction. My policy is that if you give it to me, I will review it. If you are unsure, then either call me for clarification or simply include it with your tax return records, and then I will review it. This of course will cost you for the time that will be needed to summarize your information for the tax return