Account for your time in your investment models including time spent on overhead and such...a tall order!

BUT, there are agents who are not making money right now and if an investor presented a business model that consisted of making $500 phone calls to prospect listing agents with short sales, I'm sure there'd be some agents willing to do that -- even in the land of the County of Oranges.

Run your numbers assuming different financing models.

I don't think you can charge extra rent and then have a lease clause that says you aren't responsible for maintaining the extras; but I have heard of this even being done by some landlords in the Phila area.I like to include the ceiling fans that are the low-end Lowes or Home Depot store brand models; they can be bought for like $19.99 or $29.99.

Our business model is, indeed, different than yours.

"other wise we will not make enough on replacement parts or sell as many new models."

Unless you're going to buy one of the higher end models that just came out, most of these "randomly" bounce around to room and don't clean the whole room on each run.

While it is the business model it can shrink when inflation, cost will wreck the housing industry.

Also TK model allows me to invest even by keeping my full time employment. 

I am building my investment analysis model to allow for quick and easy review of possible investments and need some guidance on some of the % values as inputs.