Many Americans treat retirement savings like a monthly bill. They chip away at it little by little, sending a few hundred dollars into their accounts every month and hoping it adds up over time. A Roth IRA is one of the most popular retirement accounts in the U.S. because of its tax advantages. Contributions are made with after-tax dollars, but the money grows tax-free. Once you're at least 59½ and the account is five years old, withdrawals — including investment gains — are generally tax-free. Charly Stoev ...