Cash back credit cards are one of the most popular types of rewards credit cards available. As each cash back credit card differs in what it has to offer, it is important to be aware of certain things about cash back credit cards, especially if you are new to the vast and plausibly complicated world of credit cards.

Here are 3 things you should know about cash back credit cards:

1. Not all cash back credit cards offer a flat rate cash back across all your purchases

Cash back credit cards are not created equal, just like travel credit cards, airline credit cards and hotel credit cards. Some cash back credit cards offer a flat rate cash back, say 1.5%, on every dollar you spend. There are no categories to fuss with, so this type of credit card is suitable for those who are looking for a hassle-free experience.

On the contrary, a cash back credit card that lets you earn rewards based on tierred cash back rates may be suitable for you if you know you routinely spend more in those categories, such as dining, entertainment, groceries, gas etc. There are plenty of such credit cards for you to choose from currently.

2. Some cash back credit cards let you enjoy bonus categories

If you don't mind the surprise factor when it comes to earning cash back as high as 5%, cash back credit cards that let you enjoy rotating bonus categories could be right up your alley. This type of credit card typically requires you to activate in order to earn the high cash back rate each quarter. However, keep in mind there's usually a limit to how much in combined purchases per quarter is eligible for earning the high cash back.

3. Some cash back credit cards let you choose your own preferred category

Depending on the cash back credit card you are looking at, some may let you choose your own preferred category among several options available where you can earn a higher rate of cash back compared to the unlimited 1% cash back you earn on all other purchases. If you are interested and there is a category option that you already spend most of your money on every month, then go ahead. This could work well to your advantage!

As a general rule of thumb, regardless of the type of cash back credit card you are interested in, try to choose one that lets you earn unlimited cash back rewards that do not expire. This way, you can accumulate your rewards without having to worry about them expiring by a certain date. Knowing that you can take your time to build up your cash back rewards, there is absolutely no need for you to spend unnecessarily just to earn some cash back.

Denise Bay is a staff writer at GET.com. Email: denise.bay@get.com.