Guardian provides submeter system design and installation, remote monitoring, automated leak detection alerts and utility bill back services. 

Loss of rent coverage if there is lets say a major leak and one of your units is down for a month or two.

After purchase, The roof leaks, I contacted the village to get the information of the contractor and  they informed me the roof did not pass inspection and the roof ridge lines are collapsing and certain areas of the roof need new decking and the shingles were not installed with underlayment.  

When the dewinterizing company went to turn on the water, almost all the plumbing fixtures leaked and they couldn’t leave the water on for our inspection without fixing some things / installing new shut off valves.If your sow is $120,000, aren’t you assuming you’re redoing plumbing and electric from scratch?

Just like you shouldn't continue with closing if you discover a huge leak in the roof, you need to delay this closing until the tenant is out.

Probably the biggest thing was that I partnered with a contractor who had a different vision for the property than I did.It was an old duplex that he envisioned as being sold only to an investor and he wanted to finish it with low-mid grade finishes (formica, wall-wall carpet, clean up the old gas stoves, etc). 

Does homeowners insurance cover leaks from one apartment into another?

When the interest rates go up a few times in 2018( say 5% or higher), gas price go up most buyers will freak out.

One thing my accountant does is deduct for gas/mileage on my work vehicle

Make sure the channel and budget fit for your goals and hit the gas hard on that medium until you like the results then move to the next medium and master it.