Sure, I'm just thinking about how sensible it is for you to buy a bigger house for the mother-in-law to move into. It's all according to Mother Nature—if she dies before you, then you'll have a pretty big house that needs to be cleaned, renovated, repaired, and heated. You will become retirees and maybe, even without a loan to pay off, you won't have that much money because the house is so big. Therefore, I would only take something with a good granny flat that can be properly rented out (not just to relatives).