When do you stop giving food when clicker training? When do you stop using treats?
In short... never, at least not completely, but it’s the same with all training approaches.
With a traditional training (based on pressure and release , -R), in the beginning there may be more pressure needed to get your horse to move or stop, but eventually you fade to less pressure needed for those same behaviors... HOWEVER you will ALWAYS use pressure to some degree.. even if it’s just a look with your eyes and your horse moves it’s feet, that is STILL pressure since the horse knows if they don’t respond more is coming. It’s the same with Positive reinforcement (+R). When teaching something new you use more positive reinforcement (scratches, food, rest, grass, etc) for even the smallest movements and changes in the horse, building on that until you have the behavior you want. We are offering something desirable to the horse (usually food) to encourage the offering of that particular behavior again.
As the behavior is more “known”/well trained/"finished" you will use less R+ for that particular behavior (so less food let's say), or use a less valuable reward (like using scratches more often instead of food).... but you will always use some kind of positive reinforcement of the horse's choice (read more here). Otherwise... why would the horse continue doing it? If there was never the need to avoid pressure or the desire to earn something desirable... why would they continue doing anything for us? There’s always a motivation behind anything the horse does for us, or in life... you can never fully remove that motivator no matter what kind of training you do. That motivator can either be something aversive (pressure, punishment) that the horse is working to avoid or get relief from, or something positive (food, scratches etc, sometimes the behavior itself can become rewarding) the horse is working to get more of. Even the most well trained horses at the highest level are STILL doing what they do for one of those reasons. Otherwise the horse would never have a reason to ever do anything we want. Just think of it this way.... there is ALWAYS some form of communication happening between you and the horse, and that happens in the form of motivation you’re using. You can never completely remove that, or there is no conversation happening, but it’s up to you to decide what kind of conversation you want to be having with your horse.