When buying an older home, if renovations have not already been completed, you should expect to replace basic systems. If the home has galvanized or plastic pipe, it may be necessary to re-plumb the whole house. The cost to do so for an average 2,000 - 3,000 square foot home to put in copper plumbing, assuming no complications, is generally about $10,000 - $20,000 depending on location. New air conditioning and heating another $10,000 to $15,000. New energy efficient windows $10,000 - $15,000. New electrical $10,000 to $15,000. New appliances $5,000 to $10,000. New Composition Roof $15,000 - $20,000. And, this all assumes there are no foundation or other serious structural issues.
Of course, all of these things don't necessarily need to be done at once; but odds are pretty good that within five years of buying an older home issues will come up related to the basic systems in the home. And, this does not include cosmetic renovations like installing a new kitchen, bathrooms, flooring etc. People generally buy older homes because they are initially cheaper than new homes and or they exist in desirable locations.
But just know that the sales price of the home is not the whole story. Renovations cost a lot of money. And, once you open up walls no telling what you will find. As Forest Gump used to say, "life is like a box of chocolates, you never know what you are going to get". The same is true when buying an older home.
