I have read that soil quality effects the life span of the foundation but have not yet done any additional research.

I did it on my personal house, it's a couple hundred bucks for soil delivered by truck (yards of soil, not a bag from menards) and some gutter extensions if it's really wet.  

Daniel, what oftens happens is that they change the carpet and never change the padding underneath.

do you have snow.. freeze thaw.. or in spring when things grow wild  LOL  or texas were your soils move and create foundation issues over time .. or in Vegas were you have no yards  but sun beats the crap out of the places LOL.. how old is the house.. etc etc. 

The soil is unstable and many older homes do not have gutters. 

My State has updated the soils classifications four times since I began design work.

Oftentimes, they get into the unit through spaces between plumbing pipes and flooring/drywall underneath sinks. 

The back yard needs to be torn up, have new top soil put down, and sodded.

My major concern is foundation/soil type in N.

Home inspectors will typically go through the attic, any crawl space underneath the house, examine the electrical, etc to let you know of any potential issues that will need repair.