If you would like to save the SMS and MMS you receive for eternity but you are worried about them occupying all your free space, there is no need for you to worry any longer, because SMS Backup is the application you need.
All your messages stored automatically
With SMS Backup you can store all the text and multimedia messages that you receive in a secure place. All you have to do is create a Gmail account which you'll have to type into the application, and that is it. With the latter you will be able to create backups whenever you want or even automatically if you prefer. These backups will be sent to your Google mail account, but you won't get them mixed up with your new mail because they will be assigned a tag which will allow you to identify them.
So now you know, don't forget to download SMS Backup because you no longer have to keep those messages on your mobile, which for one reason or another, you want to keep forever without getting rid of them.