Live-in servants are very uncommon and maybe only the ultra rich have them. What is common is to have someone come everyday for an hour or so to do chores like cleaning, cooking.
In Singapore, approximately 20% of households have a live-in maid ("helper"). Often this is not really a "luxury", simply the most cost-efficient way of providing childcare or eldercare if both parents are working, since the maids are imported from much poorer countries and paid far less than minimum wage ($600/mo, basic meals and a mat on the kitchen floor is typical).