Time is running short for tax planning in 2015. But there still are things you can do. One option: Convert all or part of your traditional IRA to a Roth IRA. You’ll owe tax on the pretax dollars that you convert. But all Roth IRA distributions are tax-free after five years and after age 59-1/2. For the purpose of measuring those five years, all Roth IRA conversions have an “as-of” date of Jan. 1 in the year you do it.