My biggest concern about investing in these cities is the possibility of a detroit scenario.

I work in an industry where the biggest selling point of the product I am working on is saving time (SaaS not real estate).

The biggest problem is the roof which should be vented from the soffits to the ridge.

I am my own biggest challenge in my real estate business.

The board and bond company will need for you to use all your efforts to the "full extent", if still unresolved, it is time for you to hire one, then the bond company will cover the cost of the next contract, up to a maximum of whatever they bonded the contractor.I would disagree with @Darnell Kramer on red flagging a contractor who needs to pay their crew, a common generalization among investors is they are looking for the biggest bang for their buck, so their typical hires are three guys with truck and tools, hopefully licensed, and mostly don't pay real worker's comp.

If they do not feel they can make a D become a C then we give them the right to fire them.The biggest cause for employee turnover in PM companies we have found is burnout of your employees.

The biggest hurdle is having the funds to complete the entire project.

[I typed in a long response while my son was preparing for bed and BP choked when I hit submit ... the "saved draft" feature did not seem to work either ... ohhh @Joshua Dorkin]  @Amit M.The biggest cost we experienced with the commercial machines was having the coin acceptor / card readers serviced/adjusted.  

The biggest thing I run into is having to add CHA to houses because they have baseboard or similar heating.

Being completely brand new to real estate investing my biggest challenges are how much money I will need for a down payment on single family rental homes and also figuring out exactly what "Investing in tax liens" is.