If you are now in or approaching retirement, congratulations. Now you can finally kick back, relax, travel, or just do nothing if you wish. However, before you unplug, now is an excellent time to make sure that your investments are optimized to give you the highest after-tax income possible throughout retirement. So, you still have some planning to do before you can really take it easy in retirement. For many retirees, the years after their final paycheck, but before required minimum distributions begin, create a valuable tax-planning window.

The two big tax-related issues in retirement are Roth conversions, and required minimum distributions, or RMDs. When you first enter retirement, it can be a bit disconcerting to realize that there is no regular paycheck hitting your bank account. However, the advantage of this situation is that as your income may temporarily be lower you may now be in a lower tax bracket, providing an opportunity to convert traditional retirement assets to Roth accounts at potentially favorable tax rates. You may also want to follow an asset location strategy where, working within your risk tolerance and asset allocation, your tax-free Roth portfolio is concentrated in risky assets that are likely to grow fastest, and your IRA is more heavily weighted towards bonds or low-risk assets as you will pay ordinary income tax on any growth in that account.

There is a saying in aviation that the three most useless things are altitude above you, runway behind you, and 10 seconds ago. As I hate to leave money on the table, I am a big proponent of the “fill the bracket” strategy where you estimate your taxable income for the year, and figure out how much money you can move into a Roth before moving into the next higher tax bracket. The goal is not necessarily to fill a tax bracket mechanically. It is to determine how much income to recognize after considering the combined effect on federal and state taxes, Medicare premiums, Social Security taxation, and other income-related costs.

Of course, there are similar strategies to minimize taxes generated by withdrawals by taking money from a Roth if you are otherwise going to be pushed into a higher tax bracket. One study by Wade Pfau showed that such a strategy of tax aware withdrawals can extend the life of a portfolio by up to three years over the basic “rule of thumb” of withdrawing taxable money first, followed by tax-deferred IRAs and 401ks, then lastly a Roth account.

According to the old saying, the only things you can’t escape are death and taxes. The government has rules about tax-deferred accounts to ensure that they get their taxes in a reasonable amount of time. The government is less worried about Roth accounts as those are funded with post-tax dollars. Required minimum distributions are the biggest way that the government ensures it gets its money from tax-deferred accounts in a timely manner. Also remember that IRAs and 401ks are the only assets that do not get a step up for your heirs, and they now have to spend down all of these assets within 10 years. This often coincides with your children’s highest earning years. RMDs can easily push retirees into a higher tax bracket without proper tax planning.

Unfortunately, these are not the only tax pitfalls that may bite you in retirement. There is the Medicare IRMAA (Income-Related Monthly Adjustment Amount) surcharges that apply to married couples filing jointly with an adjusted gross income over $218,000. Also, many people fail to plan for the Widow’s Tax where the surviving spouse pays a higher tax rate when they move from filing jointly to filing as a single taxpayer.

Your tax situation can change significantly in retirement. Having a good CPA is important, but most focus on April 15th and what happened last year. Few call you in December to suggest Roth conversions or other tax planning strategies. Taking a few hours to review your short- and long-term retirement withdrawal strategies with a financial planner can pay large dividends in the future. Like runway behind an airplane, an unused tax-planning year cannot be recovered. Before automatically taking withdrawals—or postponing action until RMDs begin—consider preparing a multiyear projection that shows how today’s decisions may affect taxes and Medicare premiums throughout retirement.