Sometimes, when you are building a home, there are certain decisions that just have to be made. Some of these decisions are fairly inexpensive when the home is under construction, but much more expensive to add once the home is done. For example, if you finish the basement of a home, you'll want to be sure you have gas lines, heat and electrical work run wherever you may need it in the upstairs because it is much harder to add those items after the basement is drywalled.
I am regretting not adding another gas line to a location where I would like to eventually put a fireplace. Had I done it while my home was under construction it would have cost me around $100. Now if I go back and add the gas line I will pay 2-300 because the drywall is done and it is much harder for the gas company to install the line. I will also have to pay the drywall guy another 100 or so to patch up the holes we would have to cut in the drywall to get the gas line installed.
The moral of the story? Prepare for the future by taking care of ground work that may be much more difficult and expensive in the future - as long as you can afford to do so.