If the house is 20 years or older, most likely the utilities are at the end of their lifecycle. You can probably bet the warranties on the water heater and air conditioning units have already expired as well. Will you be left making all the replacements? Most homeowners do not want to front the expenses associated with utility repairs or replacement and would rather move before that becomes an issue.

What condition is the roof in? Depending on what area of the country you live in, roof maintenance can come every 10-20 years. Is it ready to be replaced as well? If you've ever paid for a new roof, you know how expensive they can be. Check out the shingles to see what condition they are in. Make sure that is not another chunk of change you will have to fork over come a year or two.

Lastly, make sure you have the walls and siding thoroughly checked. Sadly, a lot of people will slap a new coat of paint over any suspicious cracks or water damage. You don't want to get in a home just to find you have to replace all the sheetrock or the wood siding. If you are buying a home in a more humid climate, mold is a major issue. You don't want to chance a member of your family getting sick down the road. Get particular and make sure you dig up all the home's dirty secrets.

The most important rule of thumb is to speak up and make sure you know what you are getting into. Hiring a home inspector isn't enough. Some of the state laws don't require enough from the inspector. Do your own homework as the buyer and thoroughly question both the seller and the inspector. Then when you are ready to sign those closing papers, you can do so knowing exactly what you are getting into.