If I increase too much, will I loose the tenants, which considering my friend's experience plus what PM said about vacancies at the moment which would be a bad thing ?

I recommend setting up keyword alerts for each area as they are discussed in the forums daily with advertisements posted in the BiggerPockets marketplace hourly.One thing to note when looking at the individual markets, you can make or loose money in any market.

Most entrepreneurs make the mistake of loosing focus on what’s working.

This causes a majority of his financial issues as his contracts exceed his original time frame then he loose money. 

Keep in mind that index funds may average 7-9% but there are specific years or event times of the year that you could invest and end up loosing money.

Interest tax deductions are great, but you only get a small percentage of the $ back (say .25-.36% so 25-36 cents per interest dollar spent) Plus what happens if we hit a snag in the economy and tenants loose jobs and or local economy tanks a bit?

The agent is intrusive and is overstepping his bounds tell him to take a hike .

@Caleb Heimsoth rightly observed that Account Closed was way too loose lipped about what they were doing.

I think this is a huge asset for owners to have licensed professionals  making sure we are staying within the bounds of NCREC laws. 

I am a firm believer in no risk no gain but all risk and living in the street if it goes south is what happens if you loose your house.