We recently had some storms in our area, and the power went out over a large part of our state. (We got our power back within a couple of days, thankfully.)
In preparation for the next power outage, we got a couple of box fans that could run off of a generator.
One of the fans seemed like a fairly powerful model — and was priced higher than other models — but when we got it home, the power wasn't that great. We expected more.
Seeing that this fan wasn't what we wanted, we returned it immediately. The danger with not doing so is that the store might think that we used it for a few days, and then returned it, without ever expecting to keep it. In essence, it might have appeared that we were just renting it for free.
The lady at the customer service center gave us no problems when we returned it.