Q. Is it beneficial to me to not have my parents claim me on their taxes anymore?
A. No. With the tax law change, effective 2018, most dependents will get the same refund whether they claim themselves or not. The personal exemption has been eliminated and the standard deduction increased. But, your parents will lose, at least, the $500 dependent credit and possibly more.
But, as others, have said, it's not optional. There is a rule that says IF somebody else CAN claim him as a dependent, he is not allowed to claim himself. If he has sufficient income (usually more than $12,550), he can & should still file taxes. In TurboTax, he indicates that somebody else can claim him as a dependent, at the personal information section. TT will check that box on form 1040.
Even if he had less, he is allowed to file if he needs to get back income tax withholding. He cannot get back social security or Medicare tax withholding.
https://ttlc.intuit.com/community/dependents/help/when-do-i-have-to-answer-yes-to-being-claimed-as-a...
