Declaring an empty element before insertAdjacentHTML

Hi I have a simple question, do I need to specify lblWelcomeUserMessage.innerHTML = ""; ( see below in code ) in the following function before insertAdjacentHTML on it ? It actually works as it is without declaring it, but I want to know what is the optimal approach ?

// Dynamic HTML / user interface for ALL users
  function showWelcomeMessage() {

      //lblWelcomeUserMessage.innerHTML = "";

      var sWelcomeUserMessage = '<h3>' + 'Welcome:' + '  ' + sessionStorage.getItem( 'name' ) + 
      '  ' +  sessionStorage.getItem( 'lastname' ) + '  ' + sessionStorage.getItem( 'role' ) + ' </h3>';
      var iUserImage = '<img src=" ' + sessionStorage.getItem( 'image' ) + ' " width="50px">';
      lblWelcomeUserMessage.insertAdjacentHTML( 'beforeend', sWelcomeUserMessage + iUserImage );
  }

It depends on what you want to do.

If you are calling showWelcomeMessage function more than once then you need to set it to empty lblWelcomeUserMessage.innerHTML = ""

       function showWelcomeMessage() {

  lblWelcomeUserMessage.innerHTML = "";

   var sWelcomeUserMessage = '<h3>' + 'Welcome:' + '  ' + sessionStorage.getItem( 'name' ) + 
  '  ' +  sessionStorage.getItem( 'lastname' ) + '  ' + sessionStorage.getItem( 'role' ) + ' </h3>';
  var iUserImage = '<img src=" ' + sessionStorage.getItem( 'image' ) + ' " width="50px">';
  lblWelcomeUserMessage.insertAdjacentHTML( 'beforeend', sWelcomeUserMessage + iUserImage );
  }

   setInterval(showWelcomeMessage,4000);

OR

Otherwise you can remove lblWelcomeUserMessage.innerHTML = ""; from above code