Emerald Club, the loyalty program of National Car Rental, offers members the chance to earn free car rentals and to skip the line and pick out your own car, along with some other perks.

Here’s what to know about National’s Emerald Club to help you decide whether you should give the company your loyalty.

What to know about National Emerald Club

1. There are multiple tiers of Emerald Club status

The three tiers are Emerald Club, Executive and Executive Elite.

Each level offers the following benefits.

2. You earn credits, not points, toward free rentals

When you’re an Emerald Club member, every time you rent a qualifying car from National you earn credits toward free future rental days. It’s the same principle as other loyalty programs’ points systems; just they call your earnings “credits” instead of “points.”

Here’s how much you earn on eligible rentals:

1 credit for a rental of one to seven days.

2 credits for a rental of eight to 11 days.

3 credits for a rental of 12 to 15 days.

4 credits for a rental of 16 to 19 days.

What are those Emerald Club credits worth?

Entry-level Emerald Club members: 7 credits = 1 free day rental of a midsize car.

Executive members: 6 credits = 1 free day rental of a mid- or full size car.

Executive Elite members: 5 credits = 1 free day rental of any car class except trucks and exotic cars.

3. You’ll earn rewards faster if you take lots of very short trips.

As an Emerald Club member, when you rent a car for a week you earn one credit. But rent seven cars for one day each and you’ll earn seven credits. So this program will be most valuable to you if you rent cars often and you can book Emerald Club car rentals for short periods of time.

4. You get the best perks when you rent midsize or better cars

Are you a frugal traveler who always picks the cheapest economy car when you rent? Then Emerald Club’s best perks aren’t for you.

Members who reserve midsize or better cars can:

Bypass the counter and go straight to the cars at any location with an “Emerald Aisle.”

Choose your own car in the Emerald Aisle area then just drive away — the keys are already in it.

About 70 National Car Rental locations in the U.S. and Canada have these Emerald Aisles. Wondering if your home airport or favorite destination offers this time-saving perk? Browse Emerald Aisle locations here.

5. You can rent cars with Enterprise for Emerald Club credits

If you can’t find a good rate or a car you like at a National car rental location, price check rental options from National’s corporate partner, Enterprise Car Rental. Rentals with Enterprise can earn credits in your Emerald Club account.

Earning Emerald Club credits from renting with Enterprise is easy. Simply enter your Emerald Club member number when you rent from Enterprise, and your Enterprise rentals will also apply toward earning Emerald Club elite status.

6. You can opt to earn airline miles or hotel points — but it’s probably not worth it

Emerald Club has partnerships with 11 airlines and two hotel groups to let you earn miles or points instead of Emerald Club credits when you rent a car. The airlines include Delta Air Lines, American Airlines, Alaska Airlines and Southwest Airlines. The two hotel partners are Hilton and Best Western.

As an Emerald Club member, you can just enter your airline or hotel loyalty program member information when you rent a car and opt to earn those miles or points instead.

For example, if you enter your Alaska Airlines Mileage Plan member number when you rent your National car, you’ll earn 50 Alaska miles for every day you have the car. Enter your Delta SkyMiles member number and you’ll earn 500 SkyMiles for your rental, regardless of how many days you rent the car.

But there’s a catch: cash fees. To earn those 50 Alaska Airlines miles per day, you’ll pay 75 cents for every day of your rental. To earn those 500 Delta SkyMiles, you’ll pay 63 cents every day of your rental.

Small change, right? Yes, but not compared to the value of the airline miles. Alaska miles are worth about 1.4 cents each, so 50 of them are worth 70 cents. With the 75 cent fee, you’re losing over a full day’s worth of points earning value, not to mention giving up the chance to earn Emerald Club credits for your rental.

Opting to earn Delta SkyMiles is a much better deal: Delta miles are worth about 1.2 cents each, so the 500 you can earn from a National Car Rental are worth about $6.00. But that’s for the entire rental period. For a one-week rental, you’re earning around 86 cents a day worth of SkyMiles while paying 63 cents per day for the privilege. And again, the opportunity cost of missing out on Emerald Club credits is worth considering.

7. Elite status can be hard to get except through a credit card

If you can earn Executive or Executive Elite status in the Emerald Club, you can get free rental days for fewer credits, plus you’ll enjoy some other perks. But, as is true for most loyalty programs, elite status is hard to reach.

To become an Emerald Club Executive level member, you have to complete 12 paid rentals or 40 paid rental days in a year. To become Emerald Club Executive Elite, you need to rack up 25 paid rentals or 85 rental days in a year.

If you have The Platinum Card® from American Express, The Business Platinum Card® from American Express or the Chase Sapphire Reserve®, you can enjoy elite status in Emerald Club as a perk of your card. Enrollment required. Terms apply.

8. You can status match

The Emerald Club status match program works with over 40 popular car rental, hotel and airline loyalty programs to connect elite travelers with more perks. Status match eligible programs include American Airlines AAdvantage, United Airlines MileagePlus, Hilton Honors and more.

Matched status is valid through Feb. 28 of the second calendar year following the member’s status match approval. To maintain matched status, members must meet the standard qualifications for each Emerald Club status level.

If you’re considering Emerald Club

If you’re going to rent a car from National, enroll in the Emerald Club. If you reserve a midsize or higher car, your membership will let you skip the rental counter and head straight to the Emerald Aisle to pick out your own car. Plus, you’ll start earning credits toward free car rentals in the future.

But before you decide to give National Car Rental your loyalty, check their locations to make sure it will be convenient for your future plans. And compare their rates against other car rental companies to make sure you’ll be getting the best deals.