NEW YORK ( MainStreet) — Gift cards are one of the most popular holiday gifts this and every year. They're fast, convenient and tend to go over well with recipients.

Some 81% of consumers will spend $30 billion on gift cards, according to the National Retail Federation.

After the holidays, consumers will be sifting through tons of gift cards, but before redeeming them, here's what you should know first:

1. Register the card

Gift cards are like cash and should be treated as such. As soon as you open the gift card, head over to the retailer's website to register the card. This way, if you lose the card or it's stolen, the retailer can issue you a new card. By registering, the retailer can keep track of the card's balance and verify you are the owner of the lost card.

2. Cards can't expire...yet

There's no rush to use your gift card. If you throw it into a drawer like most do and stumble upon it a few years later, you'll still be able to use it. You may remember the Credit CARD Act, which resulted in sweeping reform of the credit card industry.

Gift cards were also included in this law, particularly when it comes to expiration dates. Per the law, gift cards cannot expire until five years has passed since the issue date.

3. Sell your cards for cash

Chances are someone gave you a gift card to a store that you'll never shop at. Instead of regifting the card to a friend on his next birthday, make use of the card now by selling it for cash. Plenty of websites such as CardPool.com will buy your unwanted gift cards for as high as 90% of its value.

Plus, if you overspent during the holidays, why not throw the cash you make from selling gift cards towards paying off any lingering credit card debt? Remember, paying just the minimum payment on your credit card bills will keep you in debt.

On the flip side, keep in mind that these sites also allow you to buy gift cards for less than face value, which will come in handy for the stores you do shop at.

"Use discounted gift cards as a savings tool. You can enhance your savings by using a gift card along with store promotions or coupons," says Kendal Perez of HasselFreeSavings.com http://www.hasslefreesavings.com.

4. Watch out for fees

Gift cards to major retailers don't have fees, but if you've received a card backed by a credit card issuer, check the fine print to see if there's a fee to use the card. There's no way of getting around the fee, but it's worth knowing ahead of time so there are no surprises when you go to redeem the card.