Landlord insurance will cover all the hazards homeowners insurance covers plus landlord specific items like loss of rental income if there is a fire.

If he was to skim by charging more for the rehab, you then ned to be aware of the general costs to do specific items and keep an eye on that.

If there is a specific item or type of expense I can give you better guidance. 

Higher or Tahoe specific items on my P&L are as follows:Booking agency/payment processing/Advertising:  15%Housekeeping (pass thru to guest) 20%TOT (occupancy tax, pass thru to guest) 10%Spa 4%Electricity and Gas (10%)Cable(3%)Water (3%)Snow removal (2%)There are a few other line items like trash, maintenance, etc.  

Hence why just using an overall number can be more accurate than trying to itemize the individual items.Some specific items includeTaxesInsuranceUtilities (common areas, during vacancies)VacanciesProperty management AdvertisingLegal costs (leases, evictions)GroundskeepingMaintenanceMake ready in between tenantsMortgage payments aren't included.

Where it gets a little weird is if you are purchasing with a FHA insured loan, because there are specific items the FHA requires each party to pay for and doesn't allow the other party to pay.  

If you have a 25 year roof with 10 years left and it will cost $15,000 to replace, you need to budget an additional $1,500 per year going forward to cover that specific item.  

They post a basic list but then there is a list thats put into Excel which makes it easier to search and find specific items of interest as its 800 plus pages of information.

If you refurbish a property look at what you spent on specific items.

I just opened up 2 additional accounts because I think it will be easier on my QuickBooks rules to pay for property-specific items out of property-specific accounts and have QBks categorize "automatically".