Once upon a time I thought it would be a great idea to train my dog to ring bells in order to let me know she needed to go outside. Thank god I didn't. Marley and I decided she would sit by the door and I would let her out.
Marley decided this was a great training technique for ME. She now sits in front of the door whenever she wants a treat or dinner or a walk. She starts at about 6 p.m. and the human training begins. I'll see her and ask, "Do you need to go outside?" She will perk up. As soon as I get up she runs to her crate (for dinner) or to the kitchen table (for treats*). So far I have not cooperated, however she thinks I'm trainable.
I'm so happy I didn't "train" her to use a bell.
* Her treats are stored on the kitchen table.