Unless your situation is very complex, you should file your income tax return yourself. You are the best person to analyze your own tax situation and take into account all nuances and possibilities.
You are also more motivated to reduce your own taxes than the H&R Block clerk can be.
Just A Little Research and Reading
By completing your tax return yourself, you are, among other things, less likely to forget deductions. You just have to play with some numbers and read a bit; a little arithmetic and reading has never killed anyone!