It varies a fair bit by metro area, sometimes less than 10% (San Diego) other times more like 20% (STL, Riverside, CA).  

Due to the "tiered" system OPA had developed to pay varying dollar amounts per kWh, depending on the size of the nameplate capacity (size of the inverter), we found that doubling the amount of panels in relation to the inverter offered maximum "bang for the buck". 3.5 years later, the 500kW system on a 250kW nameplate capacity inverter went live (early November, 2013).Since we never had a mortgage on the building, historically, it was easy to finance the solar system by way of a new, small, first mortgage on the property.The building had a Net Operating Income or approximately $600K originally, but with the addition of this AAA, government "tenant" on the roof, we increase the NOI to around $1M.This was an opportunity which I believe only comes around a handful of times in one's life, so I'm certainly not expecting to do quite this well on every Real Estate investment.

We work with investors in varied aspects of real estate.

Frequency of maintenance inspections can vary according to property and according to tenant history.

Others are such low r/r costs, imo just take the hit on NOI and move on.I'm suggesting that NOI will vary year/year for normal wear+tear and there's nothing wrong with with that, but you're conservative approach is well founded.Many do not put depreciation into the PnL (like me) and just use it April 15. 

Remember, just because I mentioned a few cities doesn't mean I mean the entire city works.As far as size/type of home that varies in each market.

Keep in mind the laws vary tremendously from state to state.

But with all that stress, the compensation varies and comes with both benefits and downfalls.  

Having been an agent, I offer the extra thought that unless the agent in question is a broker he/she does have to split a portion of her commission with her broker.. that split varies alot between 30% - 70% avg probably being about 50%.. also you would be asking for post tax dollars   Neither of which excuse anything that even appears shady, but would make refunding money more painful for the agent.  

The floor elevation varies by about 2" throughout the house.