You have the seed to access your funds and there is a wallet backup so you can import it to another device.
Discussion
So, just to be clear. Besides the seed words, I need a wallet backup. Is it enough to make this backup only once or is it needed every time I receive new funds?
The seed is the key to your funds so you don't have to backup every time you receive funds.
The wallet backup is for the settings and contacts.
The most important is the seed phrase.