Square feet over location. They think a bigger home is better, and to make it work they pick a less desirable location. When kids get a little older and you realize the schools stink or the neighborhood isn't good, it often prompts a move. 

Improvements to increase the value of your home. Don't ever put money into an upgrade betting on a return, 95% of projects are money losers.

Other tips:

Paint yourself. Don't hire someone to paint, just do it yourselves.

You will spend more than you thought in the first couple of years. They will know you at Home Depot/Lowes on a first name basis.