as @Marcus Auerbach alluded to, out of state / remote / out of country investing is difficult... do you have everything else lined up?

Also @Andrew Syrios thank you for your opinion also, it´s pretty much helpful to have different opinions and perspectives, but still difficult to decide when someone it´s just beginning.  

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. 

It sounds like you have a lot of experience in this space, and I'm always interested in learning more.I think one takeaway is that this is a difficult asset class to own and operate, and just like @Jay Hinrichs mentioned, having a great team is essential!

The agents are charged for this service no matter what so it's difficult for the agent to service from a time and financial perspective.

That could add up quickly and might be difficult to do. 

I’ve had a similar situation before and had a difficult time finding people interested in partnering.

It's difficult to see how a tenant will be after screened and signing a lease.

I’d love to hear from fellow self-managing landlords about the biggest lessons you’ve learned along the way—whether it’s handling difficult move outs, maintenance strategies, or unique ways to streamline day-to-day operations.

Depending on your goals and how you are buying your properties you may notice that certain areas are difficult to cash flow in NH depending on your strategy and what type(s) of properties you are looking at.