Cases, I just toss, as noone will take them as recycling (that I know of), are are usually cheap-o with no resale value (eg. I've got a $10 thin TPU case on the phone, a $15 faux leather case on the iPad) and might last the length of ownership (3-6yrs), so, don't feel too bad about tossing as not going through them at any real clip.
For other things, such as chargers, cables, I keep them in a bin, in case need to replace a broken item, lend to someone. Or, put them in a different bin with other used/expired electronics, and when full, drive them over to the recycling center, as they take used electronics.