By this time of year, Libby Winslow usually doesn’t have a penny left in her healthcare Flexible Spending Account. But this year, she has been so busy at her Miami accounting firm job that she has put off some annual check-ups and doctor visits. Now Winslow has $300 to $400 left of her Flexible Spending Account money to spend by year’s end, or she will lose it.

“I usually spend it all by the end of the year, but I’ve been procrastinating things like going to the dentist,” she said.

Winslow is not alone.

Healthcare Flexible Spending Accounts are an employee benefit that allows workers to set aside a certain amount to use pre-tax for healthcare costs. But there is a “use it or lose it” rule: Any dollars left in FSAs at the end of the plan year are forfeited. (Some employers allow a grace period of 2 months and 15 days after the plan year to use up the money.)

About 20 percent of people who don’t use up all their FSA money forfeit $500 or more, according to the Employers Council on Flexible Compensation. About 40 percent of participants forfeit at least $1.

“I like having the FSA because I go to holistic and alternative doctors, who are not covered by health insurance,” Winslow said. “But I can deduct them from my FSA account.”

If you have a pot of money left to spend in your healthcare Flexible Spending Account, you’re probably biting your nails as the year draws to a close. But you don’t have to wave goodbye to your hard-earned cash yet. Here are some last-minute tips from the experts on how you can best manage and spend the rest of your FSA money:

Know when your plan year ends

Some are calendar year, but plans can end at any time of year, said Susan Luskin, owner of Diversified Administrated, which administers employee benefit plans for employers. If you do have a calendar-year plan, many companies offer a 2½-month extension, until March 15, 2013, to deplete accumulated savings in your Flexible Spending Account. Ask the human-resources department where you work about your deadline.

Check your benefits

Be careful if you have a health savings account, another tax-favored healthcare account typically used in conjunction with a high deductible plan. In that case, your Flexible Spending Account is limited to covering dental and vision expenses. The thinking is you already get a big tax benefit by socking away pre-tax dollars for healthcare spending in the health savings account.

Look for receipts

Check around for receipts for prescriptions and medical expenses you’ve already paid.

Many times, a client will find a stack of receipts in the glove compartment in their car, or tucked in a stack of papers in a junk drawer, Luskin said. If you haven’t been diligent about keeping receipts from prescriptions, and you use a major pharmacy like CVS, Walgreens, or Target, you can get a print-out of all your prescriptions from January to December.

“Then you have a one-page summary you can submit,” Luskin said.

Buy supplies

The IRS has rules against stockpiling supplies to run through Flexible Spending Account money, but the rules aren’t defined, Luskin said. So Luskin gives her clients the “three-month” rule as a guideline. “Because a prescription can be written for up to 90 days, we figure the three-month rule would pass for medical supplies,” Luskin said. For example, if you are diabetic, you could buy three months of test strips and needles. You could buy contact-lens solution or extra disposable contact lenses.