If this is your second or third time having to scramble to spend all your FSA money, why not aim to contribute the right amount to your FSA right when you enroll?
A good starting point is determining how much of your FSA funds you spent this year. When it's time to decide how much goes into the next one, you can select that amount. The exception is if you have any large expected medical costs coming up, such as a planned surgery or new baby. In those cases, you might want to add more.
If your FSA plan has the rollover option and you plan on leaving some in for next year, you can contribute even less. Though the rollover option will likely be available next year, you'll have to spend this year's funds before you dip into next year's.
Even using the money on things you might not expect is better than losing it, so pat yourself on the back for being a savvy consumer! And remember, we have easy-to-use account tools like a handy FSA Calculator to help you along the way should you need a boost.