Approximately 13% of U.S. households are now using cell phones as their only telephone service, according to the Cellular Telecommunications Industry Association (CTIA). And that number is growing. Should you be part of this cell phone only trend? It depends.

Getting rid of your landline and making your cell phone your only phone can make financial sense if the quality of your cell phone service is as good inside your home as your landline phone. Many people already rely on their cell phones for long distance calls since long distance is free with most cell phone calling plans. Other services that are not included in basic, traditional phone service such as call waiting and caller ID are included free with basic cell phone service as well. Many cell phones also offer photo caller ID, which displays a picture of the person calling if you've saved it into the address book.

On the other hand, most cell phone users pay for incoming calls as well as outgoing calls, unlike most common landline services. Sprint has some cell phone plans where all incoming calls are free. If you receive a lot of calls from outside your cell phone provider's network and you tend to be home for those calls, it might make sense to take advantage of free incoming calls on a traditional phone line. If you tend to get a lot of phone solicitations, you may rather have those coming into a traditional phone instead of using up your cell phone plan minutes.

Of course, cell phone numbers aren't listed in directories, so only people you give your number to will have it. And many cell phone calling plans offer free mobile-to-mobile calling, which means that cell phone calls to and from other customers of the same cell phone provider are included and won't count against your plan minutes.