(1) is not a given, though. If buying has a higher monthly cost than renting, that money comes from somewhere in your budget. If you are viewing your home as a

(1) is not a given, though. If buying has a higher monthly cost than renting, that money comes from somewhere in your budget. If you are viewing your home as a retirement investment (will pay off in 20 years, when you don't have to pay rent), that's most likely where it comes out of. In that case, when you take into account the appreciation on the house, you have to also consider the opportunity cost of not investing the extra money in an alternative investment.