September is the inflection point of the financial year. Open enrollment is six weeks away, FSA deadlines are three months out, tax withholding adjustments have to be made before December, and whatever financial goals you set in January still have one quarter left to address. The people who do a structured review right now have time to act on what they find. The people who wait until January are reviewing decisions they can no longer change.
Here are the six things worth checking before Q4 closes out.
Flexible spending accounts are funded pre-tax but governed by a use-it-or-lose-it rule. Most plans expire December 31, and while some offer a grace period or limited rollover, many do not. Log into your FSA provider and check your balance. If you have money remaining, eligible expenses include prescription copays, dental and vision care, over-the-counter medications, and certain medical devices. Eyeglasses, contact lenses, and dental work are the highest-value ways to use FSA dollars before year-end if you’ve been putting off those appointments.
You’re entitled to a free credit report from Equifax, Experian, and TransUnion once every 12 months at annualcreditreport.com. Pull at least one now. Look for accounts you don’t recognize, incorrect payment history, or addresses you’ve never lived at. Errors on credit reports are more common than most people expect: a 2021 FTC study found that one in five Americans has a material error on at least one bureau’s report. An unresolved error can lower your credit score by 50-100 points, which affects mortgage rates, auto loan terms, and increasingly, insurance premiums.
If you changed jobs, got married, had a child, started freelancing, or had any major income change this year, your withholding may be off. The IRS Tax Withholding Estimator at irs.gov takes about ten minutes and shows you whether your current withholding will result in a refund, a bill, or a break-even. If you’re significantly under-withheld, submitting a new W-4 to your employer now, in September, means three or four months of corrected withholding before year-end, which can eliminate or significantly reduce an April surprise.
The 2026 employee 401k contribution limit is $23,500 ($31,000 if you’re 50 or older). If you’re not on track to hit it and want to get closer before year-end, you still have roughly 15 pay periods left in the year. An increase of $100-200 per paycheck makes a meaningful difference on an annual basis and reduces taxable income for this tax year. Log into your 401k portal and adjust your deferral rate. The change typically takes effect within one to two pay cycles.
Open enrollment begins November 1 for most employer plans and marketplace coverage. This is your only window to change coverage, switch plans, or add a dependent outside of a qualifying life event. Before the window opens, review what you actually used this year: your total out-of-pocket costs, whether your doctors and prescriptions are still in-network, and whether your current plan’s deductible and premiums still make sense for your situation. Defaulting to last year’s plan without reviewing is often the most expensive decision of the open enrollment period.
Pull your actual bank and credit card data for January through August and categorize it. This is not about guilt. It’s about information. Most people’s actual spending differs meaningfully from their stated budget, and September is early enough to adjust before the high-spend holiday months. If your restaurant spending is higher than expected, or your subscriptions have accumulated, or a category you budgeted $200/month for is consistently running at $350, the time to address it is now, not January.
Your 401k contribution must come from your paycheck before December 31 to count for the current tax year. Contributions can’t be made retroactively after year-end. If you want to increase your contribution, contact your HR department or log into your 401k portal and make the change as soon as possible so it takes effect before the last payroll cycle of the year.
Some fall checkup items are FSA-specific, but most apply broadly. The tax withholding review, 401k contribution check, credit report pull, and spending analysis are relevant regardless of your benefits setup. If you have an HSA instead of an FSA, the use-it-or-lose-it rule doesn’t apply, but the contribution limit check does: the 2026 HSA limit is $4,300 for individual coverage and $8,550 for family coverage.
