I am looking for thoughts on whether I should be proactive with replacing a 20yr+ old roof (missing shingles, multiple layers, looks terrible) and a 25yr+ old hvac.

They had an excellent stay in the property but then they reported how terrible the area was and they were verbally assaulted on the street (not in the property). 

They have not been terribly lucrative for sourcing capital from passive investors.  

If there is urine there, it reacts and the smell is terrible for several days, even a week or so. 

Earlier this month I woke up one morning and "felt like" things were terrible and I quickly ran reports and saw my feeling was completely off from reality.

Most of all our zip codes are split in half with really good areas and some really terrible areas.

To make my point, if you own a property and have an amazing 2% interest rate but only cash flow $100 per month but can buy 4 units and cash flow $400 per month but have a terrible 10% interest rate all things equal would you not do it?

My 8 unit building was terribly mismanaged when I took it over so that was a learning experience bringing a building up to snuff.

And losing over $100k each month is terrible (or is that with capital improvements?).