It is highly recommended that you link your account in the game to your Plarium ID so as not to lose it. You can do this as follows: launch the game, go to Settings, open your Profile tab, and tap on "Create and set up your Plarium ID". Once this is done you will be able to restore your account and continue playing on different devices.
For the same purposes, you can connect your account in the game to your Facebook account. This will also allow you to benefit from various in-game features such as Free Gifts, The House of Unity, etc.