The problem with a ‘leave’ it command is that it relies on you always being present to give the command, and manage your dog’s behaviour.
Another approach is to teach your dog to manage his behaviour himself in a way that doesn’t rely on you issuing a command. It takes some time to re-teach if you have already taught a leave, but it does work. I am currently teaching Henry using Susan Garrett’s It’s Yer Choice method. The principle is that the dog learns never to pick up anything off the floor (or ground) or counter or anywhere unless you give him permission. Permission is a hugely valuable reward to a dog and the idea is that the reward he gets for NOT picking things up becomes greater than the gratification of scavenging.
I think it’s going to take me several months to really get the training embedded in all environments. Currently Henry’s very good at it as a ‘trick’ - like when you put treats on your dog’s paws and he leaves them until you give permission to eat them. It starts with you having treats in your hand. When the dog moves forward to take them you close your hand. He might paw or lick at your closed hand, but you just wait him out. As soon as he stops, reward with a higher value treat from the other hand. Then open the closed hand, and repeat. Within a few repetitions the dog will look at your open hand of treats and not move. He’s got the idea. It’s similar to the way many people teach a leave, but the difference is you don’t say anything. You don’t pair the dog’s decision with a verbal cue from you, because you want him to be able to replicate the behaviour by making a decision, not following a command which relies on your presence.
You extend that to not stealing favourite things in the house, then the garden, then outdoors generally You control the item when training, so if it’s on the ground, you need to be close enough to cover it with your foot or hand if the dog makes the wrong choice. It’s a slow process, especially if your dog has a long history of the behaviour you don’t want, but the principle is that the endorphins released in the dog when he knows he’s made a good choice are also a huge reward, to the point where making the ‘right’ choice is a reward in itself. I’m currently working on recalling Henry past or away from high value items on the ground at home. The point of that isn’t the recall as such, but to reinforce the choice of not picking things up: not picking things up feels good because it’s associated with a history of high reward.
If you google Susan Garrett and It’s Yer Choice, you’ll find some YouTube videos. She explains it much more clearly! It’s part of her Recallers programme which is a paid online course, but she has a few free videos out there that illustrate her method.