With those ingredients, I don't see why they wouldn't hold up in the fridge for a few days, although they would probably need to be stirred well before drinking. If you use ice in the mixture, that's a different story.
Over the summer I had a smoothie every morning for breakfast and LOVED it! My typical smoothie was greek yogurt (whatever flavor I had laying around), a banana, maybe strawberry and a splash of cold coffee. Now I'm much shorter on time and money. Anyone know how well smoothies hold up to being made a few days in advance and leaving them in the fridge? If so, would my typical recipe above work?