I never took a guided tour in Versailles (lucky you Odette!
but many of the rooms were also for royal children.
Louis XV had 10 kids, including 7 daughters and only the eldest one got married, the others stayed in Versailles. He also had 7 grandkids by his son, who became orphans quite early.
And other rooms were also reserved for the mistresses
Elissa, also the various nobles who lived in the Palace. It was Louis XIV who instituted having the nobility close at hand, 'keep your friends close but your enemies closer." So rooms were being used, often multiple occupants in one room. According to accounts of life at Versailles,
the memories of Saint-Simon, it was a filthy place, crowded and miserable in the summer. Sophia Coppela's film Marie Antoinette
touches on some of the idiosyncrasies of palace life.