What's the most expensive lesson you've learned?

Before buying your fitst home:

• bring someone with more experience than you to have a look at it, maybe even a professional
• scout out the area (on foot) during the day, evening and night
• visit local businesses like cafés, restaurants, bakeries etc.
• look at statistics like crime and air quality
• have a talk with the neighbors, get a sense of the community if you can, otherwise just observe while taking walks
• if applicable, call the home owner's representative (or whatever the equivalent is where you live), ask them about the home, neighborhood, community, expenses, plans for the future etc.
• have a set budget of how much you want to spend on it before you move in, don't overstep that amount