Without this foundation any money spent on gurus, courses, books mentorships that teach techniques and methods is WASTED, even if the methodology being taught is valid.  

Even in the nice locations, most top out around $2,800.Of course there is also your increased insurance, vacancy, repairs, CapEx, and the never mentioned reduced rent on the main house since having a stranger living in your backyard usually isn't appealing to most renters. 

Otherwise, yes you have to either excavate and repair and replace or run a pipe burst through the line, which is usually as expensive as excavating. 

Deduct NEW property taxes after you buyDeduct home insurance costsDeduct maintenance percentage, typically 10%Deduct vacancy+tenant nonperformance percentage(we recommend 5% for Class A, 10% Class B, 20% Class C, good luck with Class D)Deduct whatever dollar/percentage of cashflow you wantNow, what you have left over is the amount for debt service.Enter it into a mortgage calculator, with current interest rate for an investment property, to determine your maximum mortgage amount.Divide the mortgage amount by either 75% or 80%, depending on the required down payment percentage - this is your tentative price to offer.If the property needs repairs, you'll want to deduct 110%-120% of the estimated repairs from this amount.Be sure to also research the ARV and make sure it's 10-20% higher than your tentative purchase price.As long as the ARV checks out, this is the purchase price to offer.It is probably significantly below the asking price.

I learned this the hard way personally and had to get mine repaired.

A seller could also refuse to pay any concessions for buyers closing costs, appraisal required repairs, etc. but it would be to their own detriment.

As someone who used to work in SEO, I can see that the structure, length, and comparison format are classic SEO techniques.

So there will be the cost of the inspections (not cheap) and the cost of the repairs.  

If one or more units are vacant, the remaining units often don’t provide enough cash flow to cover expenses, making it harder to meet operating costs.Maintenance costs: A fourplex comes with four times the appliances, plumbing, HVAC systems, and other components to maintain, leading to significantly higher repair and maintenance expenses than single-family homes.If you want to see the detailed calculation, read this BP blog - More Units Doesn’t Mean More Money—Why a Single-Family Home Can Beat a Fourplex.Resale value: Multi-family properties have a limited buyer pool—mainly investors—who base their offers on CAP rates.

I have it written in my leases that tenants are responsible for clogs as well as damage from clogs. I have lengthy conversations when tenants move in about letting us know immediately if there is a clog, to stop using...