I always found that to be a very hard pill to swallow.

All of those things cost money and should be accounted for in the initial equations or at the very least, a part of the monthly rents should be set aside to build up a reserve amount, but that would reduce the monthly "profit".Maybe this property will be all sunshine and lollipops and I hope it is, but I see lots of potential pitfalls and costs when margins are this slim.  

I would say it is in that difference (let's say, for example, you're only cash flowing $50-$100 per door, arguably a slim margin) that one can better assess the risk of life events (whether your own, the tenants', or a combination of both) and how they affect your investment(s) as a whole.Those numbers are based on actual properties...I didn't just pull them out of the air to make a point. 

They can all swallow the pill of having a primary home and a second house (vacation home/seasonal residence) as a mental jump, but beyond that gets tricky, so I tend to just keep the idea to that level.

Also major banks JP morgan, goldman sachs,  etc are going to have to set a lot of money to the side additionally every month as they have to have larger and larger reserves to cover unpaid loans pilling up. 

@ Thomas LoFinding a deal on the MLS is slim pickens.

The inventory looks pretty slim from those sources.

But for my cash budget of 400k, (w/o getting hard money...) it’s slim pickings.

I am not in Detroit, but everything I read and hear would indicate that your chances of success would be somewhere between slim and none.

Those that do, are price accordingly, and profits can be slim, with no upside like condos may have with appreciation in New York.You'll need to 1) find out if they can be rented out, and then 2) run the numbers and see if they make sense.