I did my own when I was just by myself getting a salary and socking it in an Roth IRA. It's not too terribly hard for most people and families who have salaries, contribute to a few retirement accounts, kids and a mortgage. Just punch in what's on your W-2s, take the pretty run of the mill deductions and go from there. More complicated than that and it gets tricky quickly, especially when you run into questions that haven't really been directly answered by the IRS.
Now that I've got my own business and a nice stash, I've got an S-Corp, self-directed Roth IRA LLC which I rolled a traditional IRA into after converting it to a Roth , self-administered 401k trust, 529, HSA, taxable investment accounts, etc, etc. Federal taxes, state taxes, local taxes, reporting forms and requirements, and the fact I moved in the middle of the year really all make my headache. While I think I'm capable of filing my own income taxes, it's a question as to whether I'm capable of determining the LOWEST amount of tax I legally need to pay without taking deductions I shouldn't and accidentally doing something illegal. Also, as my income's grown I think I become a bigger target for an audit, so the chance a mistake comes back to bite me is also greater. Also with a higher income, missing a single deduction can easily exceed the cost of the entire preparation service. So to each his own.