So this room has the furnace, water heater, and laundry in it, and they are only accessible through this room.

You want to inspect the foundation, water lines, sewer lines, HVAC, electrical system, roof, termite, etc.  

Don't want any surprises and have to pay for a new water heater or fix a leak out of pocket!

The lender also wants the water heater to be repaired. 

Updated granite kitchen, water view, nice size lanai.

The basement has a serious water leak issues but other than that just updating of kitchen, flooring and bathroom and paint are needed.

I usually give the existing tenants 60 days notice so they have ample time to find a new home but beyond that, it's purely business.I do not recommend staggered increases over any stretch of time because that just delays the inevitable.

This doesnt account for $9.88 water charge per unit per month.Garbage - Since it is over 4 units you need to hire your own service which if you hire Flood Bros they can get you a 2 yarder twice per week for about $120 plus fees.Vacancy - Run 10% on your numbers just to be safe.Lawn - you can go on a place like taskeasy.com to estimate this cost.  

Cold calling on properties you find driving for dollars and from free lists from the county or city like water shutoff if they offer it, evictions and code violation.

Since this was my first primary residence, I didn't consider the cash-flow potential, however it was a top-floor, water view condo with it's own private roof-top deck, so I felt it had intrinsic value.