If you have a refundable ticket as a backup (on another airline if need be as AA won't allow double booking on the same flights), you can wait to cancel until shortly before departure to see if there are weather or other operational delays on their outbound flight. In these cases (delay must be at LEAST 30 minutes, maybe more) AA has allowed me to keep the inbound and get a refund for the outbound. In my case I wasn't looking to do this specifically but rather needed to get somewhere, but this strategy is better than nothing if you are going to cancel anyway.