Closing decreases your available credit, so could actually help if you are trying to get a loan.In my experience the thing that propelled my score highest in my younger days was installment loans on automobiles.

The home would typically decrease over time but the land should appreciate .

Since you are technically more heavily invested as time goes on, with more equity-or cash- in the deal, but your stabilized cash flow stays the same (or increases marginally w rent escalations), your cash on cash return would decrease year over year. 

There were a couple of times, I thought I was at risk of an increase but in every case, they stayed the same or decreased.

Goal: Increase their income or decrease there expenses so they are living in there means.  

Try to understand the cycle of the local market to see when it would be best for your to have your rentals come up for renewal in an effort to maximize your rent roll and decrease vacancy rates.

As folks get older, their ability to drive decreases.

*Mike is right on-- as your inventory of positive cash-flow properties increases, your risk decreases.

All other areas had a significant decrease, mostly double digit decreases.

Make sure to elevate it when your not working to decrease the swelling.