I've dealt with the IRS. It was a major pain. Ridiculous pain. They were contesting some education credits some years after graduation. Showed proof of payments to the university, but they responded with "Well how do we know you were paying for education - you could have been paying for things like parking?"
They kept saying "Send us this doc and you'll be good." We'd get the doc, send it to them, and they'd say it's not enough.
Called the university. They said they'd never heard the IRS contest the form that universities provide (1098 or whatever it is). I had to beg them to find my actual bill for that year, so I could show them that what I paid match what was billed. Finally the IRS relented.
Jokes on them, though. I found some unused deductions, amended my tax form, and got back an additional $400.
Having said all that, I still do all my taxes myself. Neither Turbotax nor a CPA would have spared me this headache - they would have filed it exactly as I did - just slap on the form the university provides. My wife used to use a CPA in the past - relatively cheap ($150 for both federal and state). I found issues with his work - he didn't take as many deductions as he could. I amended and got back extra money. He also messed something up which the IRS (rightly) contested. We contacted the CPA so he could fix it and he went AWOL. We had to deal with it.
If your financial situation doesn't change from year to year, I suggest paying a CPA once to do your taxes, figure out everything he/she did, and just do it yourself next year.