Has Ring security system.

Also a sprinkler system.   

Big shout out to Anson Young, his book Finding and Funding Great Deals has to be one of the best hidden gems with process driven systems for finding off market properties using listsource.com and other methods.1.

We also install a security system which helps track when they come in and go.

After filling out a permit wrong we triggered a city of Boston ordinance of having to require a sprinkler system put in.

I have searched far and wide for a company that provides a simple to use submetering system for water, electric, and heat, unless you have a 50+ unit building.

We are systemizing and partnering to grow this business.

You should not be the snitch, but if the police are to be there for you, they need to know when issues come up.You might wish to invest on a small camera system for your property.

Its quality of the contractors, quality of property managers, its not understanding the process of how to get things done in a complicated system, quality of tenant base, complexity of rental laws in Baltimore. 

I've had some luck with craigslist and messaging people on Bigger pockets, but I'm wondering what systems you guys use to build your list.