You should breakdown a phrase or word until it cannot be broken down any more. If it is possible to break it down more, then you should do so.
For example, to barbecue in French is cuire au barbecue. It is important for the student that they can see what each of parts mean:
- cuire, means to cook
- au, means to the (or here, in English, we would rather say on the)
- barbecue, means barbecue
That is why we add the breakdown, so that the student can see what the parts mean, and that is why we break down as much as possible.
As another example, in Thai, the word for slipper actually ends up being broken down into 5 parts.
So, if you can break a phrase or word down further, do so.