Ray,

The same advantage going to see your RO versus using Wikipedia to diagnose you. If you have a common cold comparing that to a very simple return with only W-2 income and not itemizing your deductions then a visit to Walgreens or in the tax world Turbo Tax (or even the IRS' own tax software)would be OK but if you have more complications in your health or tax world then a licensed physician or licensed CPA is the logical choice.

Re half pay....only advantage is you will incur less income tax.

Re medical mileage....definitely deductible as an itemized deduction. For 2008 miles driven between Jan 1 and Jun 30, 19 cents per mile and from July 1 thru Dec 31, 2008, 27 cents per mile. Remember your chances of being audited are very slim so if you didn't keep a mileage log book that few seldom do, just write down how you arrived at your estimate and keep it with your tax records.

Also deductible are lodging for you and even for someone with you to help. Meals are not deductible though on the theory that you would have to eat regardless of where you were.

When dealing with unusual medical expenses it's always a good idea to get your doctor to write a letter saying it's medically necessary and recommended. That's not a 100% guaranteed deduction but as close as you can get.

The main problem with medical deductions is that first you have to be able to itemize your deductions, i.e. expenses that exceed the "standard deduction" for your filing status plus you only get to deduct those that exceed a whopping 7.5% of your adjusted gross income which is usually limited to only those with very high unreimbursed medical expenses. Congress has enacted many Code sections that allow employers, including yourself if you are self employed, to provide medical reimbursement plans that permit you to make contributions to them with pre tax dollars and then pay medical expenses thereby avoiding the 7.5% threshold. Plan requirements do vary from simple to complex so read up on them or consult with a professional before you make a choice.