This is a common question amongst the community of juicers if you want to call them that, and it is one you may have as well. With some juicers, like the model from Breville that was documented, there will be included jars that can be used to store the juice in a cooling setting for up to one to three days. Yet, in all actuality, it may be best to simply drink the juice right after you create it as this guarantees you are receiving all the minerals, vitamins, and enzymes that come from the juice.
If you end up storing the juice properly, which will be addressed here in a minute, you can still consume all the minerals and nutrients that are provided from the juice. But, for the best, flavor it is always best to consume right away (as with most other meals).