This is NOT Business Credit.By establishing a separate corporate credit profile on the EIN Number (separate from the business owner's SSN/FICO), investors can access substantial business credit lines, capital for property acquisitions, and renovation funds without personally guaranteeing the debt.This approach creates a powerful financial firewall between personal and business assets while potentially generating a significantly larger (ROI) through reduced interest rates, increased borrowing capacity, and the ability to scale investments more rapidly.The education gap surrounding EIN corporate credit means savvy investors who understand and implement this strategy can gain a significant competitive advantage.

There are various other items that may come up such as: Proper firewall suppression, adequate entrances/exits for fire safety, stair safety, size of kitchen appliances, etc... for my specific example. 

An LLC does not provide much legal protection, it acts as a legal firewall to separate assets.

Think of them as a firewall protecting your other assets if one has a loss.

Every webserver, firewall, router, modem in everyone's house.

I learned that separation wall for a duplex could be a fire wall.

The biggest benefit of the LLC is in being able to have a sort of firewall between your companies and self.

With the government storing so much information, hackers are constantly trying to break through firewalls. 

Quote from @Sidney Duquette: Newer homes have firewalls between units and will provide better soundproofing.Nose travels much less in side-by-side units.

Easy to gain access if your company's firewalls are set to DefCON 5.