Then, there was the food. Since they had lost everything, the Potter house elves refused to serve until there was a head of house. The Potter house elves were bound to the family magics and the Potter family magics refused to help the Potters since they had committed betrayal against the main heir. That was the reason why they were kicked out of Potter manor. James still mourned that he had no access to his childhood home. The house elves felt the betrayal and refused to serve them. So, it was up to Lily to cook the food or order the cake and it was hard without the house elves. Lily was exhausted, after she was finished, but it was for her sweet child.