If they're high, I'd get suspicious.  

The tenant is good for the most part, but there are a few things that make me suspicious that there are either more people living there than listed on the lease, or possibly lots of different people staying over from time to time. 

You'll always be suspicious and that's not good.You can call your friend's father a lender, but in this case you are partnering with him, not borrowing.

If they're not then there's reason to be suspicious and concerned.Best of luck!

And even if I end up selling when moving, the right deal does seem to make sense over renting according to the nytimes calculator and so on, so long as the period of occupancy is high enough.I'll also suspiciously consider hard-money lending and other such pooling of capital, but I wonder about evaluating the capability and trustworthiness of those doing the heavy lifting without knowing much about REI myself.And thanks for keeping the real estate market humming along for chumps like me.

@Udy Ekanem explains my thoughts exactly when I see a listing with just one picture, even if it is a great picture I feel suspicious about why they're not showing off the interior.

Right off the bat that is suspicious.

Also some people who are very suspicious about the property possibly going into foreclosure.

I was suspicious at first but it all turned out fine. 

This sounds suspicious to me.