My parents had me start doing my own taxes when I was a kid (investment accounts in my name) and I've done them myself since then, with one exception. Most of those years were with pen/paper/calculator, then a few years ago I switched to TurboTax and more recently to TaxAct. Some of my tax returns have been quite complicated, including a combination of itemizing deductions, dealing with foreign tax paid, inheritance income, and Roth IRA conversions all in one year.

Even with the software I always review the actual forms for accuracy.

There was one year I decided to have a friend (casual friend) do them as she is a CPA and trying to get started in business. Ironically that was the only time in recent years my taxes were quite simple. She did them correctly but I decided afterward I just always prefer to have it under my control.