The new fourplex will put us at 5 landlord policies, and many insurance companies are telling me they will not ensure over 4.  

this means, 2 mcdonald workers living together in yucca valley could easily pay $1200/mo for a quality rental.my homes have all increased 10-20% a year for 3 yrs straight - as the few quality inexpensive rentable homes that come up are fought over by investors, new home buyers, airbnb.a sewer assessment going into effect will add 100-150 to the monthly tax burden (along with a few other assessments in the works - school,fire) Bob Armstrong (a realtor in the area) creates a nice email newsletter each month with data/commentary.

Is there any data or resource to back this up?

The basic data points as I think of them:---What is your gross rental income per booking---What is your cost per welcome basket---What is the increase in chance of a repeat booking, based on the presence of the welcome basket---Secondarily, what is the change in likelihood of a great review, based on presence of welcome basket     If you have a high gross rental income per booking (say average $5k per booking), and you can offer an incredibly high impact welcome basket at a low cost (say the basket costs $20 but includes dates harvested from the date palm trees located on the property), you will likely find this yields huge returns in repeat bookings and reviews.    

Couple things Im looking into:1) I am still discussing with my CPA but am looking at traceability options to ensure my HELOC interest is deductible under the new Tax Law 2) If I max my HELOC how is my credit score impacted --> how high will my interest become as I look to obtain refinance on a conventional mortage (delayed or 6month full refi)Overall, I think pull out what you need.

And, he is a doctor....amazing guy.The way I figure my profit is that I have my realtor friend search the data base and get a report with all the sales that closed in the past year and it shows sq ft and ask and close info.  

Stephen Burtin here in Wichita you can use recently sold data on the county website to find comparables.

Vs. simply what the data shows or condition and style be damned.

What do you use to keep track of your expenses to ensure you stay on budget for a renovation to flip a home?

And once you know why you're going over, the recommendations are generally pretty obvious.The key is that you need to keep metrics and data...