I dont want them to start drilling holes in plaster if its a pain to fill.

You could even just add it to their monthly rent so it's not a huge pain point for them up front.

While not always preached, diversification can save you some aches and pains.

Plus, it is a pain with single notes to be constantly having to do due diligence on new notes when they come due every month.

A front tenant who is a major pain in the ***, has no money, probably isn't even going to move out when she's supposed to, and has bed bugs.

Investor psychology.  

It started with some lower back pain.

They were already well aware that their rents were below market value and that the new buyer would most likely raise them (according to the seller's agent), so that eased the pain a little bit.

Also, there is the "PPD" factor - or Pain Per Dollar. 

Second, understand the "PPD" Pain Per Dollar - take time to understand the time commitment that you will need to make to manage shorter stays vs longer stays.