To Sum it up, its a good idea if you can exceed the cost of capital (higher rate than your cost of debt) with what you earn on your heloc/debt you pull out and invest.The question is how much gains above is enough to substantiate the risk of your variable interest rate, well thats up to your personal investing criteria.

As it relates to habitation exposures, it appears that there may be a leveling off in premiums, rates, and deductibles here recently, but there's so many different variables that it's really hard to make a blanket prediction for 2025 (or the future). 

I recommend you do this annually to adjust for utility increases and other variables.

Variable cost and CapEx are where I see most investors make errors on their Pro Forma.  

A HELOC offers flexibility, as you only pay interest on what you use, but rates tend to be variable.

Occasionally I catch some cleanliness issued that I am not satisfied with which I believe is due to variability in attention to detail between people on their crew, or lack of training and familiarity with my property.I've seen mentions of the value of post cleaning pictures from hosts on other forums.

Ok, next let's remove all the high risk; bye-bye sec8, D/C class, per room rentals, STRs, all that big variables stuff GONE. 

There is a lot of variability in this answer and, like all things in real estate, it simply depends. 

Next, I'd get my electrician in there STAT to give me there quote to get it done. maximum scope, account for all variables, not a "hopefully it's just..."

@Zach Howard there is no agreed upon Classification in the 1-4 unit market.We've done our best to logically create a system for our market, mostly based upon relative sale prices, but also using crime rates, rents, occupant income and a few other variables.