For our purposes we use new fans although we've been offered used fans and airconditioners.
The problem we faced when at first considering this was some needed rewiring, some needed cleaning, and the air conditioners were a liability issue. Even if they were in good working order it still was a logistical problem for us to be able to store, assess and distribute them. Right now when we order we can have the fans delivered wherever we want for free via amazon. Or Meals on wheels can pick them up from Walmart. Lifespan buys them tax exempt for us.