Also what specific dd services would you want?

Specific tips will depend on the nuances of your market, property type and property and I would recommend talking specifics with local pro's (brokers/investors) to get their opinions based on the property type/market you're focused on. 

Would love to get some opinions on self managing vs. hiring a PM, specifically in the Boston area.

Specifically how to  do it I don't know.

My Pm handles this so I can't help too much on specifics but I can tell you the judges here are way more sympathetic to the landlord so file early and file often.

However, a broker will get you much further.As for a broker in your area, there will be different brokerages that are stronger in specific types of product.

In fact most the big guys I know are using customized rules for their specific buying criteria.

I guess the correct question would be at what age of the house you sell it so it does not become a liabilty? 

I'd highly recommend checking out the local real estate networking events on meetup.com and coming to as many of those as you guys are able.One of the bigger ones, Oklahoma City Real Estate Investors Association, meets tonight (Thursday) at 7p.The investor community here is relatively small and most folks are willing to help you connect the dots.Feel free to reach out if you ever need help with anything specific!

Try and be as specific as possible with your questions.