Reply #5: The trick to Flex Spending Accounts is to allocate only what you know you'll spend.

[Gormy Cuss]

For example, if you know that there will be two pairs of eyeglasses with about $100 of out of pocket cost for each, and at least $100 in co-pays for dentists and doctors, then you know that you will use at least $300 from a Flex account and you can set it up that way.

Since without the account that $300 comes out of your pocket after taxes, it's actually costing you more than $300 to pay those little expenses, so as long as you have eligible expenses for the whole amount you will come out ahead.

Most people I know with eligible dependent care costs make out nicely with Flex accounts. Child care costs are pretty easy to ballpark.

The other thing to consider is that if you do overestimate, most Flex accounts let you use the balance for expenses in the first quarter of the next year. Check with your employer.