Question about tear down and reuse foundation

[James Masotti]

If I tear down a building and wanted to put a larger structure in its place. What are the odds that I'm able to reuse at least part of the existing basement foundation for the new building? 

Does it matter if original home was septic and new home would be hooked up to public sewer? 

What other sort of questions should I be asking on this?

Thanks as always for your infinite collective wisdom BP!