I just realized that I didn't really respond to the original question about fading food treats. I'm something of a newbie at this myself, as I did not rely heavily on treats in the past. And consequently probably use them a lot less than many people.
But the idea of using treats is that you're sort of brainwashing your puppy to associate the behavior with the reward. Once they've habituated that belief, the reward can be tapered off. But IMO not stopped entirely for at least their first year, because you need to maintain that association - i.e. good things happen when I do this.
That being said, I very seldom take treats with me when I'm away from the house, and it's worked out fine. I use treats at home to shape and reinforce behaviors. But now that my pup is 14 months old, treats only happen after a chain of commands, not for each command.
All of which is my long winded way if saying that when shaping a new behavior, treat for every step closer to your goal. Once the puppy gets it, treat only for reaching the goal. Once that's pretty well established, begin chaining commands before treating. If your puppy is losing focus you're tapering too fast. If not, keep chaining commands between treats. Just make sure to mix up the order of the chained commands or your puppy will link them together and start to anticipate the next thing rather than paying attention to you.
It's not the size of the dog in the fight, it's the size of the fight in the dog. Mark Twain