Jay's comment at the start of this thread is the most succinct and accurate assessment of D class properties you can make: 80-90% of investors will fail.I bought, self-managed, and leased out dozens of D-class doors in Hartford, CT for 4 years after the peak of the last real estate crash (2008ish) while working a full time job.

I have personally never owned a condo that DIDN'T have a special assessment - which happens when there is a repair needed but not enough money to pay for it. 

Should I subrogate for the sidewalk assessment and work done after I purchased my fourplex?.   

But for sure have an agent that is local do a drive by snap some pictures and give you a price assessment to see where your at. 

I have seen people do this a variety of ways and you should assess it more on a case-by-case basis.

A Condo's reserve account only has to be 10% of their annual assessment income in order to be a Warrantable Condo for Fannie Mae or in general.

This helps you assess the buyer's creditworthiness and ability to make timely payments.

But, if the cost is fairly nominal, maybe under a couple grand, and you have no experience in real estate, including owning your own home and hiring contractors for that, then it is likely worth it.I would always start with a deep assessment of where you feel you don't have adequate knowledge.  

Assess your savings, budget, and eligibility for homebuyer programs.

I can't tell you how many properties have units easily convertible from 1 bedroom to 2 bedroom units, units with favorable dimensional standards which can boost rents with no photos to showcase these attributes, assessment square footage that is not correct,  upgrades not identified in the marketing materials etc.