Are you expecting more guests than you planned for? What will the Mother-In-Law think if she is left waiting to use a toilet for an excessive amount of time? Don't chance your guests comfort.
Bathroom renovations can be very disruptive to the ordinary functions of your everyday routine. Don't rely on neighbours, friends or other facilities when you don't have too.
Special Events can come with several issues. Do you have enough toilets for the amount of guests? How many toilets do you need to cater for? Do you need showers for your guests?