Assembling only a few pieces of the puzzle will get you a partial picture- but if the pieces are continuous you can end up with a good starting point.
You may have a pretty nice behavior in the back yard but not anywhere else. Or you might have a great behavior - but not at full speed. Or exactly what you want, but it doesn’t hold up in the competition environment. Still it is a place to build from and you have to start somewhere.
Training without a vision of the complete picture can sometimes lead to a pretty incomplete and fragmented understanding. It can be so broken up that the dog doesn’t recognize that these are all pieces of the same thing. Some dogs will fill in the blanks with their own idea of what you want. Some dogs will just lop off the parts that don’t connect and become very good at just the pieces that make sense to them.
The biggest danger of this type of training is that you probably have filled in the missing pieces in your mind too and can't understand why your dog isn’t performing. “But we’ve worked on this! - You know how to do it!!!”
This is also a pretty common picture, where the handler knows there is a hole. This can be just a natural byproduct of not having gotten to everything yet. Or it can be a deliberate decision - for example to accommodate the dog’s temperament or past experience. It can be something that was filled in, but got lost along the way. Or something that just isn’t very important to that team.
There really isn’t any problem with this kind of picture - so long as the handler is aware of it - and doesn’t expect the dog to magically find the piece when it is needed.
In part -2 of this series, learn what each piece represents and what order I connect them (and why) when I am building a complete picture of the behavior I want.