If you are building your home from scratch you will be able to choose the floor plans that best fit your character and life style. You can choose how to allocate the area you have available and make your home unique to you!
You can plan ahead on ways in which you can reduce your yearly expenses. A good example is insulation. It is much more efficient and effective to do this while building rather than including this to an already built structure.
A newly built home will require less maintenance than a home that has been standing for a number of years already. In addition, you may use material and build in such a way so as to have lower maintenance requirements.
Including features that cater for your safety needs will be easier when building your home from scratch rather than having to adapt an already built structure.
Your new home will have warranties that may last for the first couple of years on several amenities purchased and also on work that has been performed on your house. This may also serve as a security against major expenses in the first years after moving in.