I try to use only fruit. Banana, pineapple, raspberry and strawberry. That's the best I found. Today I added some orange juice I made and it was even better. 

I wouldn't recommend juicing leafy green. Put then in a blender if you want some. If your talking about masticating juicer, I don't recommend them. I would probably run with the juicer you have until it dies. Maybe it can last you another year or even more. 

Masticating juicer are too slow, only best at juicing wheat grass or green and I don't really recommend this. I've seen plenty of people eating only fruit. There's no need for leafy green not matter how much mineral and vitamin they pack. Fruit are easier to digest. That said, leafy green can sometime be really appetizing. Spinach and lettuce in particular.