In addition to regular IRA contributions as described above, special catch-up contributions can be made annually to both traditional and Roth IRAs if you are at least age 50 by the end of the calendar year. For individuals who meet this age requirement, the regular contribution is increased by $1,000 in 2013 (same in 2012). This catch-up contribution is based solely on your age, and is not affected by the amount of contributions you have made to an IRA in the past.
Your choice of whether or not to invest in an IRA will be influenced by whether or not your contribution is tax-deductible. If you're a low- or middle-income taxpayer, part of your IRA contribution may be eligible for a tax credit. See the section Choosing between the Roth IRA and Other Vehicles.