Soffit is not just a functional part of the home, it also provides an aesthetic purpose too. This is the part of your home that covers your eaves. Without this, in place, you would be able to see the beams of your home.
It is important to have the soffit of your home professionally installed. If the soffit is incorrectly placed on your home, this can allow moisture to enter parts of the home that are unprotected.
Also, the soffit installation will not last nearly as long as it should. The goal of any soffit installation is to make your home better protected from the elements and also look nicer too.