When I first got my pack for my dog, I just put it on her every time we went on a walk. The pack was always empty. She didn't like the pack, but forgot about it as soon as we went out the door with the leash. Over time she associated the pack with the leash as something that goes on for walks. The walk is the reward. I eventually put weight in it, but she didn't care because she was going for a walk.
I've taken a vow of poverty. To annoy me, send money.