Here are a few common pitfalls to avoid:Overpaying for a Property – It’s easy to get carried away in a bidding war or buy a property without doing the proper math.

You're right I should have done better math here. 

Based on my quick math, if we go with the 30yr option and save ~$1070 in monthly payments for the next 15 years (this is based on ~$580k of currently outstanding mortgage), we would need to invest that ~$1070 at a ~9.8% compounded rate in order to be able to break even between those two options i.e. fully pay off the 30yr mortgage at the end of year 15.

There are a couple opportunities thats on MLS currently, and I am crunching through my math and it seems to work out well (positive cash flow, decent cap rate).Some key assumptions I hope still holds true today:  low vacancy rate in general. ~1000-1200/month for a room in a single family house / duplex. 

Answer here lies in the math.

I do like your math. 

Doing the math, I would lose 16k if they called the loan the very next day.

Do the math, see if this would allow you to add even more value to the property for resale down the road.

You’ve received some pretty thought out answers already so hopefully I will not repeat too much of them.At the end of the day, this is a business and turnovers in my experience are way more in expensive than several years of rent increases combined … so you have to do your math and figure out whether it would be worth losing this tenant if she decides to go elsewhere.

For me, it's all about the math.