Every puppy comes to their new home with an inherent desire to follow. They are always underfoot and look to you for guidance and entertainment. Then something happens...they turn 16 weeks and realize that they can be independent.
If you do it right, teaching your new puppy to come back when called is the easiest skill to solidify. Your puppy is already showing you the desired behaviour. All you need to do is reward it, praise it, solidify it. By rewarding their desire to follow, you are creating a solid foundation on which to build your recall. If you wait until they are 16 weeks old, you will have to work exponentially harder to make recalls fun and rewarding.
Make life easier for you and your new pup - start training from day one and always reward the behaviors you like.
Erinn Lee Dog Training