I think you're right to be concerned - as to the paranoia, Just because you're paranoid doesn't mean they aren't after you (or your client in this case).

First, you do know that mileage is allowed ONLY for passenger vehicles, right? IRS Publication 43, Page 17 defines which vehicles qualify. It says, in part - "a car is any four-wheeled vehicle (including a truck or van) that is made primarily for use on public streets, roads, and highways. Its unloaded gross vehicle weight must not be more than 6,000 pounds." If this guy is moving big parts, like boilers, HVAC units, furnaces and other large items the truck may be TOO LARGE to use the standard mileage allowance. Ask to see the vehicle registration and look to see what the weight is (note that is NOT the vehicle weight RATING which is different). If its too big you'll have to use actual expenses.

For the moment, let's assume you do qualify to use the standard mileage allowance.

The rules do require an accounting of mileage. HOW mileage is accounted for is another question altogether. I've had very good success at audit substantiating mileage from appointment books and route sheets that show scheduled appointments or stops. You can use Google Maps, Yahoo Maps, MapQuest or just about any decent mapping program to get the business and commuting mileage.

The actual mileage is a bit harder, you'll need something to show the total miles. cpaboise pointed out that oil changes and regular service records typically show odometer readings. These are helpful but I've only seen the IRS ask for this when mileage is HIGH.

IMNHO, 30K mileage a year is NOT high and certainly is NOT excessive in my experience. Though I must say that I'm in a rural area and I have no idea where you are. I do have several plumbers and other construction workers as clients and their documented mileage is closer to 50K+ a year. Personally, I have an office in Central Delaware and Annapolis Maryland - its 53 miles from one to the other. That works out to 106 miles a day, 424 miles a week (4 days) and over 20K miles annually AND that's just between the two offices and before I count my mileage to clients, seminars, CPE classes and audits.

Frankly, I don't think he is any more at risk of audit by filing late than by filing to begin with.

Do make sure you have an engagement letter that spells out the requirements that he maintain a record of his mileage and that you are NOT responsible should the IRS audit and audit and disallow the deduction.

Also, check to see what the mileage will do to his AMT situation. Making that kind of money and itemizing he may well be into the AMT. If so, check to see how many miles he can claim before triggering the AMT. You may just find that the usable miles are lower, and thus more easily swallowed.

Good luck

You are not being paranoid, and this may or may not trigger an audit.

Remember, first and foremost, the information on the return is the responsibility of the taxpayer, not the preparer.

If your client's mileage will be audited, the IRS will likely look for substantiation of odometer readings from an independent source (vehicle purchase record will have a starting point for date and odometer, vehicle oil changes and tire rotations performed by auto maintenance shops regularly record odometer readings that can be compared to current readings). If the client can't/won't provide independent verification, the deduction will typically be disallowed. Also, if the vehicle is the only one available, the IRS may disallow part of the deduction due to percieved personal usage.

As for the tools, no receipt, no deduction.

Before you begin this engagement, make sure you have a comprehensive engagement letter signed by the client and he is aware of his responsibilities to provide accurate and complete information and have the appropriate records. Do not automatically assume they exist. And ask to see the mileage log (though you are not a forensic document expert and may have no way of knowing how old it is), and remind your client that records must be kept contemporaneously. Help him devise a system to do that.

Also, ask if his company has any reimbursement policy for use of his tools or vehicle - if not, have him get a letter and keep it in his files for just in case - the IRS will ask for that as well during an audit.

Agreed with Boise. If you take mileage, I would put a note to the return stating that contemporaneous records are NOT available, but that there are records to substantiate the deduction.

Since he is W-2 as well, make sure to take commuting mileage. He MUST go to the shop or something each day. I get lots of these clients in FL and they try and "forget" that commuting is part of the equation.

How large of an area does he travel? 30K business based on 250 work days a year is 120 miles a day!! To me, this is high unless he is very rural and has to then COMMUTE again to the city to begin his day. That then is not deductible.

Your looking for an audit and for them to yank your license. You should never claim mileage unless your client has detailed records to substantiate it.