You can continue contributing to an individual retirement account until you turn 70 1/2 as long as contributions do not exceed your earned income. After that, your eligibility to contribute depends on what type of IRA you have.
Traditional Vs. Roth IRAs
If you have a traditional IRA, you are barred from making contributions, and must start taking distributions, beginning the year you turn 70 1/2. Roth IRAs do not have this rule--you may contribute earned income to your Roth IRA accounts as long as you live.
If you take part in a simplified employee pension or savings incentive match plan for employees (SIMPLE) IRA through work, your employer is obligated to continue making contributions on your behalf even if you are 70 1/2 or older. However, you may also be required to take distributions at the same time.
Contributions to traditional, SEP and SIMPLE IRAs are tax-free; distributions are subject to income taxes. Federal government rules set contribution age limits and required distributions to increase the chance that owners will pay taxes on IRA assets in their lifetime. Because Roth IRA distributions are tax-free, there is no rationale for requiring owners to make withdrawals in their lifetimes.