I’ve paid between $1500 and $1900 for 10-13 properties over the last 20 years.

The ROI / punchline: I've already 100x'ed this investment, i.e. it's paid itself back 100x overShe did not ask for this review, but I had such a positive experience that I had to make the time to write it.

While this affiliation might bring certain advantages like integration and streamlined services, it’s also worth noting that many tech entrants in the property management sphere sometimes miss the intricacies of real estate management, focusing heavily on financial aspects instead.If you're looking for alternatives, you might want to consider other established platforms that specialize in property management, like AppFolio or Buildium, which are paid services but widely recognized for their comprehensive features and security measures.

Their rent covers about 2/3 of our monthly expenses.

I am in the process of doing a foreclosure in SC right now and it is long and pretty expensive (this was a NPL I purchased).  

Even if you have money for the 20% down, it's not wise to spend your last dime making that down payment and leaving yourself vulnerable to losses from a bad tenant or maintenance costs.If you want to be a successful investor, increase your earnings, reduce your expenses, save up, and buy wisely. 

In the grand scheme of things, yes, you should eventually replace the windows so 1) They operate properly. 2) It doesn't turn away potential tenants or cause maintenance hassles when a new one moves in.3) Tenants have proper egress in case of an emergency (like fire).Now, windows are expensive, so you'll have to decide how much you're willing to spend, based on how much income the property is bringing in.

Just checking my math.This is obviously after all expense , depreciation, cost set, property tax write offs, 20% etc.my question is are my assumptions correct? 

Worth it IMHO.I agree with @John Underwood that it shouldn't make too much of a difference.You can always charge the guests less and then expense the difference.

I've used Quickbooks for years but it isn't really tailored for rentals and has become very expensive.