2017 is rapidly coming to a close, and there are some things you really need to do with your taxes before the year ends. With tax reform efforts ongoing in Washington, there's a high likelihood that 2017 will be the last year you'll be able to take advantage of some key tax breaks.

If you think that Republican lawmakers will succeed in passing a bill that includes most of the provisions that they initially proposed, then considering some of these tax moves before Dec. 31 is a must. Below, we'll first look at some possible moves that you should consider as "use it or lose it" items, and then turn to more general year-end tax tips.

1. Take full advantage of state and local tax deductions while they're still available.

One likely casualty of tax reform for taxpayers will be the itemized deduction for state and local taxes. This provision includes not only a choice between deducting income or sales taxes at the state and local level, but also your property tax payments to government entities. If you've already paid the bills that were due in 2017, consider whether you can make early payments toward your future tax liability. It's when you make the payments that matters for purposes of deductibility, so if the deduction goes away in 2018, then paying sooner than you otherwise would have to could be the only way to get a tax break at all.

2. Complete a planned home purchase if it exceeds $500,000 in value.

There's disagreement about whether the mortgage interest deduction will survive in its current form or not. The initial Senate version kept the current mortgage interest provision unchanged, allowing full deductions on a purchase of up to $1 million. But the House version would reduce that limit to $500,000. Most people following the situation expect that existing mortgages will be grandfathered in, so if you're looking at buying a home in the $500,000 to $1 million range, getting that done sooner rather than later is your best hedge against the House version winning out.

1040 tax return with a pencil on top of a spread-out pile of U.S. $100 bills.

Image source: Getty Images.

3. Pay off sizable medical expenses before the end of the year.

Another conflict between the two Congressional tax proposals involves medical deductions. The Senate version would allow taxpayers to keep taking medical expenses above certain income-based thresholds as an itemized deduction, but the House version would eliminate the deduction entirely. To be on the safe side, if you foresee needing expensive medical care before the end of the year -- or if you've already incurred sizable healthcare costs -- then you should think carefully about paying bills before Dec. 31 if they would help you to qualify for this itemized deduction.

4. Prepay student loan interest.

Currently, many taxpayers can deduct the interest they pay on their student loans, but the House version of tax reform would eliminate this deduction. That's a blow to many taxpayers, because unlike many tax breaks, the student loan interest deduction doesn't force you to itemize in order to claim it. You might be able to make a January payment early and claim some additional interest, but going forward, if the tax break goes away, it could be a smart move to pay off your loans sooner than you otherwise would have.

5. Educators: Pay classroom-related expenses early.

Another break on the chopping block is the $250 deduction for money that teachers and other educators spend on supplies for their classrooms. This small item reflects the effort that many educators make in an era of tight municipal budgets, but if the House version of tax reform wins the day, then the deduction could go away. If you qualify and haven't paid your full $250 yet, consider doing so before the year ends.

6. Accelerate other expenses that would qualify as itemized deductions.

More broadly, the tax-reform package would dramatically increase standard deductions, making it less valuable for many taxpayers to itemize. Even if popular breaks like charitable deductions survive, it might not do you any good to itemize them if your standard deduction is so much higher than your total itemizable expenses. Whether you're looking at charitable gifts, tax preparation costs, casualty losses, or a host of other miscellaneous itemized deductions you can make, consider getting them prepaid in 2017 so you can claim them on this year's tax return

7. Get your retirement plan contributions done.

Going beyond tax-reform-related moves, if you're part of a 401(k) or other employer-sponsored retirement plan, making sure you get as much money as possible into your account can cut your taxes. The general maximum you can set aside for most plans is up to $18,000 in wages, with those who are 50 or older getting to save an additional $6,000 if they choose. Unlike IRAs, 401(k) contributions must be completed by Dec. 31, so talk to your HR department to see if you can get more money taken out of your end-of-year paychecks in order to take maximum advantage.

8. Get your portfolio losers sold.

Losses on investments are deductible against gains, reducing the amount of tax you'll pay on winning investments that you've sold during the year. To claim your loss, you need to sell the losing stock by Dec. 31, and then make sure not to buy it back within 30 days. Even if you don't have gains on other investments, up to $3,000 in capital losses is available for offsetting other types of income.

9. Arrange to have income deferred into next year.

Most people can't control when they get their paychecks, but some entrepreneurs and self-employed workers have the ability to time their income to some extent. If you think that tax rates will be lower for you in 2018, then deferring income until after 2017 can be a smart move. How exactly to accomplish this depends on the accounting method that you use in your business and a host of other issues, so make sure to consult your tax professional to decide exactly how to implement an income-deferral strategy.

10. Make sure you're not going to owe a tax penalty.

Last but not least, it's important to estimate your taxes and make sure that you've had enough money withheld to avoid any penalties. The general rule is that if you've had at least 100% of your prior-year tax liability withheld, or 90% of what you'll end up owing this year, you won't owe a penalty. But other requirements apply to high-income taxpayers. If you're short, then boosting your income tax withholding from your paycheck can be the best way to remedy the situation.

Finish the year tax-strong

No one wants to think about taxes during the holiday season, but making these moves before 2018 begins is crucial to ensure you won't run into nasty surprises. Keep your eyes on Washington to see what emerges on the tax-reform front, but be prepared to take action -- even if there's no final resolution -- to cover your bases.

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