During the lazy dog days of summer, taxes are probably the last thing on your mind. But the middle of the year is an ideal time to review your 2024 tax return and look for ways to lower your 2025 taxes before the months fly by.

“A midyear tax checkup can help you avoid unintended surprises later, during the filing season,” says Eliot Bassin, a certified public accountant in Avon, Connecticut. “We don’t want people hearing information for the first time in April, when a tax bill needs to be paid.”

Here’s a rundown of items to go over now.

Paycheck withholding and estimated taxes: If you received a large refund or owed a substantial amount for 2024, you may need to make a midyear adjustment.

Taxpayers are supposed to pay the IRS and state governments throughout the year rather than all at once, when they file their tax return. If you’re an employee who receives a Form W-2, that’s usually not a problem, because your employer withholds taxes from your paycheck.

However, if you have non-salary income, such as from self-employment, gig work, investments in a taxable account or withdrawals from a tax-deferred retirement plan, you may need to make estimated payments based on what you expect to owe. The payment deadlines for the 2025 tax year are April 15, June 16 and Sept. 15, 2025, and Jan. 15, 2026.

Ideally, your paycheck withholding or estimated payments will end up close to the amount you’ll actually owe. Pay too little and you may fork over late-payment and underpayment penalties. Pay too much and you’ll get a refund, which means you’re giving the government an interest-free loan.

You can adjust your withholding by submitting a Form W-4, listing your total income, household situation and applicable deductions, to your employer’s payroll department. To estimate how much you should have withheld, use the IRS’s tool at www.irs.gov/payments/tax-withholding.

For estimated taxes, do your best to approximate what you’ll earn for the year and how much you may owe based on your current income and your past year’s tax bill. You’ll avoid penalties if you pay 110% of what you owed in 2024 or 90% of what you end up owing for 2025 through withholding and estimated payments.

Retirement plans: IRAs, 401(k)s and other retirement plans allow you deduct contributions and defer taxes on your investment gains. For 2025, you can save up to $7,000 in an IRA if you are younger than 50 or up to $8,000 if you are 50 or older. A 401(k) allows up to $23,500 if you are younger than 50; up to $31,000 if you’re from 50 to 59 or you’re 64 or older; and up to $34,750 if you are from 60 to 63.

Depending on the plan rules, you usually have until Dec. 31 to make 401(k) contributions. With IRAs, you can make 2025 contributions until the tax-filing deadline in April 2026. Now is a good time to assess how close you will be to maxing out your contributions and whether you can save more before the deadline.

Health insurance tax credits: If you buy health insurance through a federal or state health insurance marketplace, you may be eligible for a tax credit for your premiums based on your income and family size. With that in mind, consider whether you’ve gone through any significant life changes this year, such as getting married or divorced or having children. These circumstances could affect your premium tax credit.

If needed, update your account information to take advantage of lower premiums from tax credits you aren’t using or to avoid being charged back for credits you’re no longer eligible for when you file your 2025 tax return.

Health care saving and spending accounts: If your job offers a flexible spending account, you can put aside part of your income, before taxes, to spend on health or dependent care expenses. Most FSAs have a use-it-or-lose-it rule: Whatever you don’t spend by year’s end — or by March 15, if your employer offers a grace period — will be forfeited. Map out a plan to spend down your balance.

If you have a high-deductible health insurance plan — meaning a plan that has a deductible of at least $1,650 for individual coverage or $3,300 for family coverage — you can contribute to a health savings account. With an HSA, contributions are deductible, your investment gains are tax-deferred, and withdrawals for qualifying medical expenses are tax-free.

Like retirement plans, HSAs cap your annual contributions: $4,300 for individuals and $8,550 for families in 2025 (account owners who are 55 or older can contribute an additional $1,000). You have until April 15, 2026, to max out HSA contributions for 2025, so now is a good time to confirm that you’re on target.

Charitable donations: If you donate to charity during the year, you may get a tax deduction. Keep in mind, however, that you must itemize on your tax return to take advantage of this break.

“Many taxpayers put off charitable planning until the end of the year,” says Jeff Kelson, co-leader of EisnerAmper’s National Tax Office in Iselin, New Jersey, who notes that waiting can lead to a scramble to make sure the contributions are made in time. By reviewing your donation plans now, you can strategize how to support your favorite charities while maximizing tax breaks.

Long-term planning: Midyear is a good time to meet with a tax professional, especially if you’re going through significant life changes, such as moving, changing jobs or sending your kids to college. “There can be tax implications for even the most mundane-seeming things,” Kelson says. Plus, you’ll likely find that it’s easier to set up a meeting with a tax pro now instead of right before the April filing deadline.