Reducing the use of food rewards should be a goal when training dogs, but always be ready to to use more or better treats when you add distractions, duration or distance to a behavior. Here’s a good excerpt on the subject from a book sold by Whole Dog Journal. It’s up to you if you want buy it, but the practical training tips are good to share with pet owners.
Source: Whole Dog Daily, January 3, 2017.
Once your dog knows a behavior well, and can perform it in many locations and with many distractions, you can fade the use of your marker signal and rewards. In other words, you don’t need to click and treat every time your dog sits for you. However, it’s also important to pay off every now and then to keep your dog in the game and gambling.