However, it is good to get into the habit of doing so, especially if you plan to scale. 

I still believe that both strategies play a vital part in one's portfolio for, if nothing else, diversification. 

The habits will determine your success.

Here's my very basic but vital advice that I've been preaching for years: obtain a W2 position that you genuinely enjoy and/or are interested in.

I too need constant reminding that its not worth doing it myself most of the time....hardest habit to break.

The value offered is very hard to quantify and too easy to fudge.Also, in my experience, the biggest obstacles to success are rarely technical; rather, they are nearly always about your mental state, habits, and beliefs. 

My apologizes for leaving out that vital piece of info!  

If you get a tenant who makes a habit of not paying rent - they likely know how to game the system and can drag the eviction out for months.

I don't know, do you normally make it a habit of pissing away $36K? 

If she wants to stay tell her that the apartment she rented is how it will stay and only repairs necessary for habitability will be done.