When should i remove livedata observer on android?

I am observing a list in firestore using LiveData . This observations is dependent on another authentication LiveData.

Should i remove the old LiveData observer before creating the new one? What will happen if i don't?

Currently i am removing the observer using next code but i can simplify it greatly if i won't need to since i do the same all over my code

override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
...

//Authentication observer which is the ItemAuto dependent
viewModel.auth.observe(viewLifecycleOwner, Observer {auth ->
            updateUserItemAutoLiveData(auth)
        })
}


private fun updateUserItemAutoLiveData(auth: Auth) {
        if (!auth.uid.isNullOrEmpty()) {

            removeUserItemAutoObservers()

            itemAutoLiveDate = viewModel.getUserItemAutoLiveData(auth.uid)

            itemAutoLiveDate!!.observe(viewLifecycleOwner, Observer {
                if (it != null) {
                    if (it.data != null) {
                        itemAutoCompleteAdapter.submitItemAuto(it)
                    } 
                }
            })

        } else {
            removeUserItemAutoObservers()
        }
    }

private fun removeUserItemAutoObservers() {
    if (itemAutoLiveDate != null && itemAutoLiveDate!!.hasObservers()) {
        itemAutoLiveDate!!.removeObservers(this)
    }
} 

ps: i am using Doug Stevenson tutorial which is great!