Roth IRAs offer a bit more flexibility than traditional IRAs do. You may withdraw your contributions to a Roth IRA penalty-free at any time for any reason (but you'll be penalized for withdrawing any investment earnings before age 59 ½ unless it's for a qualifying reason). If you converted money from a traditional IRA into a Roth IRA, you can't take it out penalty-free until at least five years after the conversion.
Roth IRAs also let you leave your money untouched for as long as you like. With a traditional IRA, you must start making withdrawals called "required minimum distributions" after you reach age 70 ½. And while you can no longer make contributions to a traditional IRA after you have turned 70 ½, you can keep contributing to a Roth IRA regardless of your age.