It’s more than junior waste a lot of time and are generally not very productive. Life gets easier after because people get better at what they do.
Edit: For the people downvoting me, you have to understand that a senior in consulting is basically someone which can do the work by themselves without being babied. A junior is there to learn and hopefully help on simple things. I routinely produced more contents that some of my juniors on projects as a manager despite spending a tenth of their allocated time on it. That was fine. You don’t magically get good at consulting. You have to put in the time.
Edit: For the people downvoting me, you have to understand that a senior in consulting is basically someone which can do the work by themselves without being babied. A junior is there to learn and hopefully help on simple things. I routinely produced more contents that some of my juniors on projects as a manager despite spending a tenth of their allocated time on it. That was fine. You don’t magically get good at consulting. You have to put in the time.