Our dog Winston wasn't allowed on the couch for the first year we had him. Dogs need structure and we liked clean furniture, so it worked. Of course, Winston realized the couch was a comfy place that smelled like mom and dad, so he would occasionally sneak on the couch when we weren't looking. Even though he would always jump off if he heard us coming and would act like he wasn't there, the warm spot he left behind was pretty obvious.
Eventually we started allowing Winston on the couch occasionally. He gets couch time a few times a month (more over the holidays, when the weather is really cruddy, or one of us is feeling sick) as a special treat, but he does still sneak up on his own without being invited. Instead of hopping off right away when he gets caught, he sometimes waits for you to ask him to move, just to see if you'll let him stay. These photos were taken on a dreary, rainy day when I caught Winston on the couch and didn't have the heart to move him.
All photos with a Canon 5D Mark II and 50mm f/1.4 lens. Processed in Lightroom using some Lightroom presets from Light Stalking and Lightgram.