I honestly don't know a single investor that would proceed with the same offer if the contractor/inspector told them there was an unforeseen issue that costs $40,000 to fix.While this doesn't happen often, and our intention is to get it all right the first time, we can't be 100% accurate on repair costs all the time.  

I'll throw this to you...a quick and dirty little estimate, numbers are labor+material based on what I've spent recently...Insulation - $6kDrywall - $10kInterior doors/trim/shelving - $8kInterior paint - $8kFlooring - $12kCabinets - $15kCountertops - $6kElectrical fixtures - $2kPlumbing fixtures - $2kShower/kitchen tile - $8kHardware - $2kGlass (shower doors) - $4kDisposal/trash - $3kRough/Final cleans - $1kAppliances - $3kMisc/unforeseen - $5kTotal - $95k and he hasn't made a profit yet.It adds up quickly!!!

With every house we ever buy, there's always a chance of something unforeseen going wrong, right? 

What if my duplex turns out to be a nightmare (Unforeseen expenses and repairs, Bad Tenant, ETC)Any insight on this is greatly appreciated!

The cons of building new are: 1 - Unforeseen expense increases due to supply chain issues, high labor demand resulting in higher costs, Contractor not budgeting correctly, etc.

This allows you to identify any areas where you may be overspending and take corrective measures in a timely manner.Allow for Contingencies: Set aside a contingency budget to account for unexpected expenses or unforeseen issues that may arise during the renovation.

Have you ever had to leave in the middle of an episode for an unforeseen reason leaving the other host to keep going without you? 

Having a financial buffer can help cover mortgage payments and other costs in case of tenant non-payment or other unforeseen circumstances.4.

I try to focus on my short to medium term goals because anytime I set a goal further than a few years out so many unforeseen things change it is no longer valid.

Understanding the scope of work as a Project Manager will help you get ahead of the potential unforeseen circumstances you're almost certainly going to be faced with.