Let's assume that the neighborhood is a C class and the median income of the city is greater than 3X of the market rent.Here are some of the considerations I've come up with so far:- Units are in need of renovation and capex is too high or not available- Unit quality is not the same as market - Seller is worried about losing tenants due to increase- Vacancy rates are high or filling units have been difficult- Rent increase would take multiple increases over multiple lease periods to get to market rate if seller is trying to retain the same tenant- Seller inherited property and just want to liquidate- Seller needs to liquidate quickly (financial burden, sickness, quick exit from land-lording)It seems like I might be missing a warning sign about a deal if they are selling with current rents that are under market; but again, this seems to be most of the properties I've underwritten.And in the same vein, what should I be worried about when purchasing a deal with under market rent with the intention of raising them after purchase. 

The major pieces of information you are missing include NOI which includes deducting all of your operating expenses from your gross rents sans debt service, market dynamics (what are vacancy rates and asking rents like in the market the building is located in?)

Use your superior knowledge, experience and analytical ability to spot something in a property being offered for sale that everyone else has missed.  

A young population plus a growing industry makes for good long term investments, but unless you are really scaling the cashflow can be hit or miss. 

For your $240K new-build townhouse, a cost seg may make sense if the tax savings outweigh the study cost (~$3K–$6K), especially since you plan to hold it for 10+ years and can benefit from immediate bonus depreciation.For the $380K older townhouse, cost seg with look-back depreciation could provide significant one-time deductions for missed depreciation over the past six years.

I think you're missing another point-- if rates increase.

Unless you're in the right market, traveling nurses can be hit-or-miss.

Do you feel like you may be missing out on deductions? 

If you missed the window for completing the repairs, that is on you.

I'm looking into 1/1MF, 2/1MF for now I feel bad about one property that I missed out on due to procrastinating.