Sell? Swap w/ friends? Return if not opened?

I know you won't know whether your LO likes certain products until you've tried them. So what if they don't like something? Or you never needed it? What if the packages are opened? What do you do with all that stuff?

For example, what if you wanted to BF and got all the equipment, but had to quit after a few weeks/months? What if you got some swaddles and LO is not a swaddler?