What are the pain points of a property manager? Being an investor of buy and hold real estate, I wanted to understand what keeps PM's up at night. 

Originally posted by @Jenny Chu :

What are the pain points of a property manager? Being an investor of buy and hold real estate, I wanted to understand what keeps PM's up at night. 

 Tenants.

Bad tenants (work really hard at not having any or getting rid of)

Bad vendors (Easy to deal with, don't use again)

Bad owners (Cheap, won't take care of property, which then attracts bad tenants and bad vendors)

The key word is "bad".  Good tenants, vendors and owners are all required for successful real estate investing.