At some stage in your life, you will run out of living space in your house. Selling up and moving to a larger home in a new an new area is usually your first thought, but can be a daunting experience. When you move house, you never know what you will get into. Will your new neighbours be as nice as your current neighbours?
Will your new environment be better or worse for your family than your current environment? Moving would also attract great costs, running into the tens of thousands. If you are happy where you live now, extending you home suddenly becomes a safe alternative