On my duplex, the water is not split (electric and gas are separately metered.)

It has some foundation damage and the electrical panel is outdated.

But in my Airbnb seminars here in Denver I've also heard from hosts who weren't covered for some basic things, like bed bug remediation. 

There are a lot of questionable items with the electric.

I, like many others, caught the bug for real estate investing after reading Rich Dad, Poor Dad. 

., possible old plumbing and electric.  

I based my numbers off what my annual tenant was giving, plus any additional expense like electric and cable I would have to pay for now. then ran my numbers.

@Joe FreyIf you are redividing the property into two units, why not simply put separate electrical and, if present, gas entrances into the second unit?  

The places i've seen has the plumbing/electrical/HVAC so its a fair simple go.I will admit I spend $2000 on cameras, and exterior lighting.  

Best way is to obtain authorizations for release of credit, tax returns, assets and liabilities, then send copies or get several originals to use, mail them  and obtain information directly from the source, this cuts out the chance of fraudulent statements.You also need to underwrite the type of business, what hazards are present, toxics, fire, insurance coverage, competition with other tenants, traffic counts, environmental laws applicable to them as well as your infrastructure being sufficient for tha use.....electrical, plumbing, traps, fire codes, etc.